You can on any iOS device without jailbreaking. Look into AltStore or Sidestore. The caveat is that you can only sign 3 apps at a time, and must resign these apps every week - which is done over your WiFi to a PC running AltStore server.

If you have a $99/year Apple developer account, you can use AltStore to sign as many apps as you like, and you only need to resign once per year.

But that version of alt store does not support installing uyouplus. At least I have not been able to add the repo.

I’m trying to imagine voluntarily buying a device that all but prohibits you from choosing the software you run on it. A limit of 2-3 apps, which have to be re-signed weekly by a desktop server, to me that doesn’t count as “supporting sideloading.” Maybe technically. What a joke.