Can I undo the trade?

I need urgent help. Yesterday I agreed to swap with someone from the internet on Facebook (Messenger). I swapped my PC (worth 1500 euro) for a laptop. Of course, I made sure that this comes my PC equivalent. I was told that the laptop does not cause any problems and that all games run smoothly. Unfortunately, this is not the case, which of course I have noticed only after the exchange and the laptop is much worse than my PC. I mean the exchange partner should have made it clear to me that hardly a game is running smoothly, not even on lowest settings. It's really cheeky to say that every game runs smoothly! No exchange exclusion was agreed by both exchange partners. What can I legally do about it? I really want to have my PC back because it's just so much better and it makes me mentally ready to have such a garbage laptop now.

So I'm a little confused now.

Of course, I made sure that this comes my PC equivalent

How did you do this? Every computer has specifications, it's easy to see how good something is.
So how exactly did you pay attention to this?

Did he lie to you about the specs or did it rather follow the motto:

"Hey, can I play modern games on it?" - "Yeah, that's not a problem"

If he has clearly told you the untruth, then of course you can do something about it. But it depends on what you have discussed.

Maybe it would be interesting if you tell us the specifications of your old PC and then sometimes the specs of the bad laptop. If there's a significant discrepancy in value here, then one could certainly consider the trade as invalid. Here we might be even with malicious deception. But without more context, of course, this is only blue.

The initial consultation with a lawyer usually ALWAYS costs something, the question of the cost of the same.

First and foremost, you should contact your barter and tell them that the promised features of the laptop are not the ones he promised you. Then wait for the reaction.

The laptop works that's just fact. Whether this laptop is worth your PC is another question.

You could go to an electronics shop with this laptop and see if the functionality of this device is limited, or if this device is usually running the way it is.

If you find that the laptop has any defects, then inform the exchange partner and ask for the exchange to be reversed.

If he does not agree, you will probably only have to go to the lawyer, which I would tell the exchange partner.

A specialist will also be able to tell you whether your PC is much higher in value than the laptop.

Of course, we can't know what has been agreed between you two here.

Then you have a bad lawyer. So far I have had to consult a lawyer in various matters and never paid for the first consultation.

well, that's not very extensive. But at least I learn a.) If there's a chance at all and b.) Where you can start approximately…

fair enough, one has to say that one must then trust the lawyer so far…

Many Thanks! Talking helped. The exchange was reversed.