Piracy: ꜱᴀɪʟ ᴛʜᴇ ʜɪɢʜ ꜱᴇᴀꜱ

you mean, run non-steam games on steam deck, using your existing files?

if so, you'll need to transfer them and duplicate what the installer does, in a Wine environment like proton, and that's prone to error and subtle necessities, like this or that software / windows component not being present. it's honestly not worth it. you can't (or usually can't) do this windows->windows, and it's even harder to go windows->Linux (wine).

if you mean, transfer the steam games from windows to deck, then just enable local sharing.

I run totk exclusively on my steam deck (I liked the fact that load times were faster on steam deck than original switch)

you will need to find a stable version of yuzu that will work on it and you should be able to get about 30fps fairly consistently with performance mods. (there is a totk optimizer you can run that has a steam deck setting built in. very convenient)

bg3 I highly recommend trying to get the native steam deck version for it. cause it runs much better.

I use microsd cards to move files around. so if you have those I recommend them.

Localsend

Isn't that a Nintendo Switch game? You'd need to install and run an emulator for that, like you did with Yuzu on Windows. I don't think Yuzu is around anymore, but there are some sucessors, Eden and Citron? I'd install one of those. At least Eden has SteamOS mentioned on it's homepage. You need to install it, though. The SteamOS or Linux version from their homepage, not copy the entire emulator over from Windows. After that you can transfer the game files and load them into the emulator. Any variant to copy files between computers should work. A windows network share, USB stick, microSD card, a cloud drive or filedrop/sync tool...

I do not have a Steam Deck but I do use Linux.

Doesn't it have a Micro SD card slot? That would probably be the least faffing way to copy files.

Aside from that it's just a Linux computer so anything you like; I'm partial to SSH (rsync) for one off or Syncthing to sync folders around. You could also use a magic-wormhole web client, a Windows shared folder (no experience connecting to SMB shares from Linux), or croc (like Magic wormhole but resumable).

Also not a user of pirated game files, but what kind of format are they? If they are EXE files then they won't work when you double click them like on Windows (at least not unless SteamOS went to the effort to configure that). You have to run them with Proton from Steam. I do not know how to do this with things outside Steam but you cauld try adding them to Steam as an external game, then the usual "select Proton" configuration might present itself.

You should be able to access the laptop in some way. If it is an actual seedbox there may be some tool for access built in, or you could use ftp or similar file server software on the laptop, router or the Deck itself. For me, kdeconnect works sometimes but USB absolutely does. You may have some different underlying issue, maybe something's broken? I'm downloading most of my games on the Deck itself anyway since using two devices at the same time feels more tiring.

Get the files transferred from what? Your Win11 laptop? Because it's reasonably likely that the files won't work properly if transferred- Windows executables don't just work on Linux.

Also what games specifically are you trying to play? For BG3 you'll probably need to find the Linux version or get Proton set up. For TotK you can probably use most of the same files, but you'll need a new emulator install. There's roughly a thousand Switch emulators so pick your poison and following the install instructions.