> But Apple doesn't give me a legal way to freely run an iOS simulator nor even a macOS VM on my linux machine, I have to pay money, to buy their hardware to see if my site will work on Safari.

Try GNOME Web (Epiphany). It's webkit based, keeps up with Safari, doesn't disable access to the Safari devtools, and it sends the exact same user agent string. Should be essentially bug-for-bug compatible. It's otherwise an anemic browser, but you don't need much for testing.