It's not as good as Xcode, but you can set up a serviceable Swift dev environment on Linux with VS Code and the official Swift VS Code plugin which adds LSP and debugger support. It's easiest to set up in Ubuntu and Fedora but should be possible in in other distros.

I haven't toyed with Swift under Windows, but the devs behind Arc Browser have been hiring people to work on improving Windows tooling and writing a Swift wrapper for WinUI 3.