is target disc mode compatible with a pc?

No, you cannot use Target Disk Mode to connect to a PC. Windows has absolutely no idea how to read/write macOS formatted drives. And depending how your Mac failed you might not be able to do so. If your Mac can’t even startup you can’t enter Target Disk Mode anyway.

The only solution I can think of is to remove the drive from the Mac purchase an enclosure to install it in. But you’ll still need a Mac to access the files. There are utilities for Windows that allow a PC to read Mac formatted drives but I have no idea of they are worth anything.

Finally, did you not have a backup of your Mac to use?

Technically it will work with any PC if the PC has the proper ports, but Windows isn't able to read the macOS drives/file systems. There may be third party drivers that can be installed on Windows to do this (Paragon I believe supplies a third party driver, but I've heard their drivers may cause issues with the OS).

If you are familiar with the command line, then you may be able to boot the Mac into Recovery Mode or Internet Recovery Mode to transfer your files to an external USB drive. If you don't have another Mac, then it would be best to use the exFAT file system on the USB drive so Windows can read it. It is usually best to use macOS to erase the drive since Windows may use an a block/cluster size with exFAT the macOS may not understand.

If you are familiar with Linux, then this may be an option as well although it is a bit tricky to mount the volumes within a Core Storage or APFS container (requires the use of the command line to mount a Mac drive). While in theory Linux can access a Filevault encrypted drive I personally have never been able to do so, but I also have not spent much time trying either.