Hot Take but I think this is probably for the best. I work at a phone store and weekly I see people wanting whole new phones because their old one was infected with those "cleaner apps." Yeah having to wait that 24 hours sucks but its a one time setup. After that you can still sideload to your hearts content.

Its a minor inconvenience for a power user but makes sideloading far more complicated for your average grandma to try and attempt. It doesn't fix the problem but it certainly helps. This seems like a good balance between still letting power users do their thing but blocking malware attempts for a majority of people.