I agree, the most likely scenario here is that somebody found the OP's seed. Let's say it was stored in a safe. Somebody found the combo, or somebody found the key. Remember, OP: they don't need to steal the paper your seed is written on. They'd just take a picture of your words. That's all they need to steal your coins later.
Even if the PC is infected, a seed generated by a hardwallet cannot be exposed, since it was generated on the device itself, offline
Ledger hardware uses closed source code, so there's no way to prove that is true. Sadly. It is possible that seeds on Ledger hardware can be accessed over the internet. The code is closed source, so we just don't know. I wish people would stop making assumptions about the safety of devices that run closed source code.
Closed source code is like a meal where the cook won't tell you what's in it.
Closed source code cannot be trusted, because closed source code cannot be verified. Anyone who says otherwise is someone you should not trust, if you value the security of your Bitcoin.
To the OP
I saw that you started your wallets in 2022, and it was only in 2023 that this balance was moved, which following logic, must not have been a hack at the time of creating your wallet but something later, since a hack would make the transfer at the same time as it had access to your wallet
Probably, but not necessarily. There's always the chance that somebody who hacked Ledger's code would sit on keys they acquire in order to not let Ledger know their code has been hacked. I don't think this is likely in this case though, but it's a possibility.
I strongly suspect that when the code for Ledger gets hacked, we won't know about it for months, if not longer, because the hackers would want to steal as many keys as possible before Ledger realizes there's a problem, since patching the code would cut off the hacker's access to stealing people's keys.
Closed source code cannot be trusted, because closed source code cannot be verified. Anyone who says otherwise is someone you should not trust, if you value the security of your Bitcoin.