You can convert all your markdown files to org in one go using pandoc.

I quit discord a year ago for Matrix or XMPP. never looked back.

That is definitely not a good starting point. WSL is much more complicated and prone to breakage than running a distro directly. It litteraly changes the whole system to make Windows run on top of a hypervisor. A better way to try out GNU/Linux is to boot up a live environment on a USB stick or use a VM. Plus, WSL is only command line, and I would think that showing a friendly desktop environment is the best way to blow the assumption of GNU/Linux being hard/only for nerds.

At the start I dual booted but after some months I realised everything I could do on Windows I could do on GNU/Linux, only my computer would run faster on the later and actually did what I meant. I tried to battle Windows to configure it how I wanted and it was a real pain in the rear end. My advice is go for the full switch and nuke Windows. I never looked back since.