You used to be able if you could restore a backup you made on a previous phone version.

This has been a massive pain point for app developers who want to test their work on different os versions.

the latest jailbreakable version for an xr is 16.5.1 which is no longer signed so you won’t be able to jailbreak your phone. However, if you’re just trying to sideload apps then you might want to try altstore + livecontainer (to bypass the three app limit).