Like you, my device is showing it's age. It's not been my daily for a few years but is used for alarms and keeping a copy of some IT manuals available locally within arm's reach. The keyboard could do with a replacement, backspace key has worn off, keys need cleaning/ transparent letters have yellowed. I had an SD card give up a few months ago. Very early 64gb card, split into 2x 1gb swaps with rest as data. Read works fine, write doesn't. Phone reboots, laptop says it has written file but it disappears on removal. Replaced it with a 128gb configured the same.

I looked at Planetcom, Gemini and Cosmo, but not sure on specs. The FxTec 1 X looks more like it spec wise but it's in a crowdfunding project. Still haven't found that true N900 replacement. Last few years I've had a OnePlus 3T, also now showing age and battery wear. Might get a 9 next year. For now my Pi4 4Gb is having to support my interests.