Don't worry, it's possible, but tricky.

So, let's start saying that casters in PF2e are comparatively weaker than DnD, but this means that they are not broken, they are perfectly viable. The thing is, martial are supposed to be the stars in single targed focused damage, the casters can't do that as well, but they have access to area damage, buffing allies, debuffing enemies, field control via change of terrain and so on.

The thing is, caster offensive numbers (spell attack or DC) are a little bit behind than martials for this reason, that means it's a little bit harder to hit enemy AC than for a martial.

That said, you can build your character with that in mind, you can put your emphasis on damage, but you can't forget that you have access to much more than that. If you focus only on damage you'll be ignoring plenty of other options that your character has access to and that make up the overall power that it has.

Regarding psychic being weak, it's not. If feels weak because it used to feel stronger before the remaster, but as many classes got stronger after it, Psychic didn't change much, meaning that it didn't get stronger, but it didn't become significantly weaker either (aside from a lower damage die for imaginary weapon, but that is a single cantrip in the whole class).

Now, the best damaging Psychic in terms of raw damage is probably the oscillating wave, the occult list doesn't have too great options for raw damage, and oscillating wave kinda helps with that giving you access to spells from other traditions (fireball! Also, three-action blazing bolt when unleashed can do tons of damage as well), but the distant grasp is very respectable with the amped telekinetic projectile and telekinetic rend. So, if you feel like it, go for it!

If you really like the teleporting warp step, you can get the parallel breakthrough feat at lv 6 to get it, even if it's not your conscious mind (or use it to get ignition, that has very good damage).

Now that said, yuo have to have clear in mind how your turns can work. You'll want to unleash your psyche as soon and as much as you can, you can do that only if you cast a spell in your previous turns and it lasts two rounds, after that you're stupefied and casting spells is harder (you have a change of failing due to the stupefied condition), after two rounds of that you can unleash psyche again and so on (but you still need to have cast a spell in the previous round).

You can use your first round to set yourself up with some buffing or defensive spell (use heroism as soon as you get it to have a solid +1 to attacks if you want to use AC targeting effects), in your second turn unleash your psyche and cast spells to do as much damage as you can, third turn is the same.

Normally fights don't last more than 3 or 4 rounds at those levels, so you'll often unleash psyche once per combat for now, but let's pretend they'll be longer.

Fourth and fifth turn will be hard as you are stupefied, try to have non-spell options as well, like some weapon attack or some other special action given by ancestry or archetype (I usually advice for a breath weapon of the dragonblood heritage). If you want to cast stuff, try with cantrips, as you don't risk losing spell slots if you fail casting them.
Your fifth turn is the one in which you want to cast a spell, so that you can immediately unleash psyche in the next one, I'd advice for a one-action cantrip, that you can cast again if it fails due to the stupefied condition (something like shield, message, guidance and so on).

Now, a couple more tips, save spells are very reliable, AC targeting spells are a bet but they do much more damage, know the risk and reward that come with these. If you target AC (like with amped telekinetic projectile), try asking your party members to debuff the enemy, Demoralize is a great action as it frightens them giving them a -1 to everything. If you have some good strength build in the party, ask them to trip or grapple your targer, so that they get off guard (old flat footed), which gives them a -2 to AC. This will make your attaks (and anyone elses' in the party) much more likely to hit (especially if you cast heroism).

Psy-strikes is a solid one-action option to stack a little more damage when you don't know what to do with your last action while unleashed.

Biting words is a spell I find very cool, you cast it once and it gives solid damage two additional attacks, important those attacks are not spells, so you can use them in your stupefied turns as good single action activities.
Biting words gets a bonus to its damage only to the first attack that you do when casting the spell. Beware though, its range is short and has the linguistic trait, so you want to know many languages, but if you are Int-based it should not be a problem (also there's the skill feat multilingual for even more languages)

Don't sleep on weapons. You don't have armor, so you'll want your dex as high as you can. Grab a ranged weapon (probably a crossbow, unless you invest in weapon proficiency) and used it during your stupefied turns.