Honestly I agree. If you want sideloading, here’s the great thing about competition, you can go with a competitor that allows that.
I regularly swap between iPhone and various androids specifically because I want different things sometimes. I don’t want iPhone’s niche to get screwed up - one of their biggest selling points is their tailor made walled garden experience. It’s sure as hell not for everyone, but for those that like it, it’s fantastic.
And for the record, I say all this as someone who usually goes with Android.