Safari is a very thin set of changes to WebKit, you can just run & build WebKit nightlies, which I do for web dev, so I don't screw up my main browser. You have zero idea what you're talking about, you just read a wiki page.
Macs let you run anything you want, obviously. iOS does, too, as long as you're a developer sideloading. People who can't hit compile shouldn't be allowed to run random shit on their phones which are 2FA etc. keys.
Safari is a very thin set of changes to WebKit, you can just run & build WebKit nightlies,
you don't seem to understand software licenses, so please stop overselling yourself. Just because a software uses open source code, it doesn't automatically become open-source. You're first claim was Safari is open-source. It's not
You clearly didn't spend any effort trying it, learning how it works, or reading the license. It is literally a browser, just not named Safari and using your saved preferences, which is a good thing when you're developing. Not that you can.
you need pay a subscription every year to publish your app on the app store. You can sign your app and install it but it's temporary and you need to repeat it every time it expires afaik.
But you need a mac for it. Don'tyou just love Apple's fancy walled gardens?