Also, there are many apps from sanctioned Russian companies that can't be published on Google Play, so they only exist in alternative app stores like RuStore and/or as self-updating apks.

On iOS, they just can't "legally" have an app any more, period. Some made their apps PWAs, some say "just use the website", and some (Tinkoff/T-Bank in particular) keep trying to get into the app store with those double-bottom apps and also distribute them signed with enterprise certificates.