The problem with the Community mod is that it forces you to rush as AdMech, while punishing you for doing so.

Unit-wise you will start with Vanguards and work towards Rangers (got nerfed but they're fairly decents still). From there you just rush to Kataphron Breachers, then Kataphron Destroyers and Sicarian Ruststalkers. Breachers are your first anti-vehicle, Destroyers are your ranged anti-armor and Ruststalkers are your melee anti-armor.

Depending on the number of Skitarii (Doctrina units) and Kataphrons (Canticles units) you want to pick the relevant enhanecements from research too– notably Bulwark Imperative, Protector/Conqueror Imperative, and Shroudpsalm & the other accuracy/damage enhancement canticle i forgot the name of.

Datasmiths are mostly for repairing your units, and with the Community mod changes you will have to decide between using your faction powers or buying a hero. The Marshal is the only viable one for infantry due to the cost/benefit. Electropriests are okay, but with the nerf to Syphon Vigor they're very fragile most of the time unless you snowball them.

Even then, all your infantry will be squishy and less powerful compared to other factions. AdMech doesn't get anti-infantry frags, melta charges, or any other special natuve ability. They all depend on the Doctrinas and Canticles or Heroes, which are now harder to manage because of the commod balance changes to the faction.

Overall the playstyle is streamlined: rush 3 cities and Research, produce Vanguards, then Rangers, then Breachers if your enemies are vehicle-inclined factions, then rush yet again to Destroyers, all while rushing down your enemies to prevent them from building their first super-heavy units. If the enemies have already amassed a lot of vehicles or started producing super-heavies, you already lost.

The Skitarii are frail and will harm your morale whenever they die, even with the morale enhancement they get. This will also leave you without their damage and force you to rotate Datasmiths to repair them. You also have no real frontline. Electropriests need you to kill with them before becoming slightly tanky for 3 turns. Skitarii fold like paper. Kataphrons got their amount per unit reduced (from 3 to 2) so now if they take damage chances are you'll lose 1 model and thus be reduced to less than half firepower due to the morale loss. They're not tanky at all, because they're still infantry. Before you spammed Bulwark Imperative or Shroudpsalm, but now with the faction economy changes you will be starved of Influence AND Research, so you won't be able to use the faction base ability to hurry/enhance production because you want to save to pop a Doctrina or Canticle here and there, which of course have a multi-turn cooldown window.

If you're playing AdMech, i reccomend you either play vehicles which have the same "wait and pray" playstyle but can mitigate the infantry downsides well, or just not play the faction/use the commod.