but the dedicated Windows button has been replaced by a RISC-V button. There’s no news yet on what function that button might provide
What it does will depend on the desktop environment and/or application, but I'd expect it to be the "Super" key, which is the same binding the Windows key has under most Linux distros. Use of the Windows logo requires following Microsoft's branding terms, so Linux laptops and some custom keyboards/keycaps choose to replace it with either the word 'Super' or some alternative logo.
The DIY keyboard I typed this on actually has the letters "Win" written out as a workaround so they don't have to deal with the "Microsoft Windows Logo Key Logo License Agreement for Keyboard Manufacturers".