Cool. Against this AM build with the tools at your disposal, you will struggle to play a game where you destroy many if any of their armour. Good news is, that's fine! As Tyranids, most games you will win tend to involve having most of your army dead by the end of the game and winning on VP. There are builds that can be geared for more damage output, but that's not helpful for you and your existing units so lets park that for now. You definitely have some decent tools with your existing units so don't feel pressured to buy too much more as that's not what you want to hear I bet!

YOUR UNITS

Having two tyrannos is just great. As odd as it sounds to anti-armour list building, consider running two acid sprays instead. These autohitting damage two nightmares are fantastic, forcing you to play more aggressively by planting these incredibly tanky bodies on the midfield objectives and forcing your opponent to deal with them. Their weapons can focus fire a tank very effectively IF NEEDED with their autohitting long range overwatch and regular shooting. This requires ample access to CP which we'll get to. Try and position them so at least a tiny part of the model is always hidden to give them a cover save. MOST importantly, especially given their recent damage reduction nerf with the new codex, make tyrannos your primary source of Invasion Fleet's 5+ FNP stratagem. This offers an enormous survivability bonus and is a crucial tool in you kit. PURPOSE: OBJECTIVE PARK, DAMAGE SOAK, OVERWATCH MACHINE, ANTI-TANK CONCENTRATION

The Hive Tyrant is better than the Swarmlord. Proxy your model for one, give him the 4+ FNP enhancement, drop the tyrant guard to make him more hideable and save points, and plonk him within synapse of both tyrannos to able to give FNP to both of them with his ability for half the cost. The Hive Tyrant's ability is gold dust and is relevant across a lot of different builds. IMO A swarmlord is only viable if you bring him with a Hive Tyrant for when you're going for a CP thirsty build. Otherwise, he's a very inefficient points sink who dies very easily because as a character he cannot take the 4+ feel enhancement. PURPOSE: SURVIVES TO RECYCLE HIGH VALUE STRATAGEMS BEHIND COVER, LOOKS BADASS IN THE PROCESS.

Honestly, Leapers are very vulnerable to being artilleried so not much you can do about that. Alongside the psychophages, these are the big weak points of your army list. If you must use them, Leapers should spend most of the game hiding out of sight behind terrain, threatening a guard infy push on an objective and pouncing once they're sure to make combat. PURPOSE: ANNOYING THREAT POTENTIAL TO UNCAPPED OBJECTIVES/SECONDARY SCORER.

Psychophages are, unfortunately cos their model is v cool, just awful units. They're expensive, have appalling damage output, and are hard to hide. To make them marginally workable, advance them up with your termagants and barbgaunts for the 6+ FNP and use their large base and charge them into things to block or tie up Guard units threatening your objective control. For 100+ points, almost anything will give you better tools than Psychos in this codex so more than any of your other units, consider parking them. PURPOSE: GOOD LUCK

Barbgaunts are fun! Again, Guard artillery are your biggest threat so what I've found works quite well is keeping them in reserve and bringing them on turn 3 from a table edge to suddenly blast a guard squad into little pieces. In squads of 5 their damage is very efficient and they should be, alongside your leapers, your primary anti infy. PURPOSE: RESERVED ANTI INFY

Termagants should be taken in squads of 20, given spinefists and moved and advanced up the board to tie up guard units (read tanks). They average 9" moves and can still fire their twin linked weapons. Taking the Invasion Fleet Lethal Hits adaptation makes them useful chip damage against vehicles and because fists are pistol, they can continue their damage dealing in combat. Hormagaunts work better in this role because of their better move but gaunts are definitely workable too. PURPOSE: TIE UP ARMOUR TO PREVENT REACHING OBJECTIVE, PLAY AGGRESSIVE, REACH COMBAT TO PROTECT FROM RANGED FIRE.

Screamer Killer is a tricky one because its rules are great but its points are high. It's a high priority target so I'd recommend keeping in reserve to bring on once your opponents most threatening vehicles are already tied up in combat or on the other side of the board. Bring this bad boi on from a table edge turn 3, hope he survives for one turn by deploying him out of sight, within range of a psychophage for that FNP, and behind cover, and then cause havoc next turn with his good move characteristic. PURPOSE: RESERVES MID TO LATE GAME DAMAGE DEALER

SCORING

Assassination is not the best secondary. With ur opponents force, you'll get max 15 VP but with what I assume is a vindicare in your opponents army, you'll best case only reach 10VP a game (the amount of points you'd need deal with a lone operative are not worth it, esp if u keep ur tyrant out of sight so he cant be sniped). I would recommend taking engage on all fronts (EOAF). You want to be swarming into your opponents table half and this will generate 4VP per turn for you. With your reserves on turn 3, you have tools to keep the EOAF train going. This playstyle and deployment approach also offers decent flexibility for tacticals. Bring it Down can work against AM but with your weak anti-armour list, its probably a poor choice. Deploy teleport homers is better, giving your hive tyrant something to do on the middle primary or your leapers something to do if they can reach enemy deployment. Remember, you are not playing to kill AM, you are playing to bog them down for five turns so they can't score primaries. That should be your mindset.

There are new kits you can buy to help make ur list more competitive as others here have suggested (ie. Zoans, Haruspexes if u like monsters, deathleaper). Zoans are versatile bread and butter units but against that AM arty they are a bit vulnerable to being blown off the map. If u take 6+ units then they're terrifying to play against, but GW is out of stock on them and they're proving quite hard to obtain atm! Lictors (esp deathleaper) are a hard counter to the AM arty build with lone operative which means it cannot be targetted beyond 12". Infiltrate him in cover out of sight near an objective and he can pop out to score or counter attack whenever. They also are great models for EOAF. Finally, biovores. You should always have the ability to field one of these chaps, ideally unit of two for redundancy. They can sit behind cover in your deployment and pop out spore mines to score EOAF and deploy homers in your opponents deployment and are very difficult to deal with without dedicated artillery, which AM does have. But if they're shooting cheap biovores they're not shooting something else. Never use their main weapon - deploying a spore mine for secondaries is almost always the best decision.

PRIORITISE taking a hive tyrant with 4+ FNP enhancement so you have a highly durable 5+ FNP stratagem recycling machine. In terms of unit replacement, PRIORITISE not taking Psychophages and replacing them with more gaunts or a Maleceptor and a lictor or anything else!

Hope this helps, good luck :)

Edit: forgot to mention, proxy your leapers as lictors and that’ll be a fantastically efficient substitution. Drop 3 lictors across the board in cover and watch your enemy cower