Thanks for sharing your experiences: To conclude your post for myself:
upgrade to 4.6 if:
if you are ok with new owner’s terms of service
(which I haven’t forwarded to my legal team to assess yet.)
if you have a specific fix or feature in mind that would make it worth
(I did not see a must have in the release notes - still waiting for Jollyboyz to implement a paid feature: integrated secure communication hub with clients for SIP, XMPP, all your modern video call clients, only for clients in free countries of course, hehe)
if a tester actually confirms the fix / feature to work without introducing new annoyances like battery draining faster
(not saying this is the case as you state but historically in 2024 this is to be expected over smart device industry )
if you have a data backup and/or backup device.
(I have a Xperia X and N900 which I would be happy to be stuck with)