I replaced the Nexus 7 with a Pixel C with the folio cover, which has been my favourite gadget ever, honestly. Versatile, portable, etc, but I don't think they make them anymore. If you can find a 2nd hand 64gb version, I recommend them though.

There are likely much cheaper and HW-wise more up to date Android tablets out there, but as I'm happy with the Pixel C for now, I haven't done any research, so not much help from me there I'm afraid (:

I sadly had to put one of the household's Nexus 7 to rest. Symptoms not entirely like yours, except for the eternal boot times. Mine ended up being so laggy it was impossible to use.

Good luck!