If you want to play with some of the UIs and apps, check out the devices postmarketOS supports [0]. Especially Snapdragon 410 (MSM8916) support is looking pretty good, and the devices are quite affordable used (low to middle double figures, or you may even have one already!). Generally, postmarketOS is just awesome, the abilities of their pmbootstrap tool alone are amazing.

[0] https://wiki.postmarketos.org/wiki/Devices