You can do that already.
If you own an iPhone, it's actually very practical to also have a Mac.
> run a specific software at least once a week, and limited to like 3 apps.
What?
The most common way to make all this signing a bit more bearable is to have AltStore installed on your mac, which will automatically re-signs the select few apps you want in some hacky way (needs your Apple id and password).
Don't you find it ridiculous that the "common" way to run software written by you on a $1k device that you bought is via buying $2k machine and paying 99$ yearly?