First world problem for sure. 😅
Personally I collect watches, nothing fancy, just some retro styled digital watches, mostly Casio and Timex, but also some other brands. Since none of them are for show only, I also have to decide daily which one I want to use and the more my (small) collection grew, the bigger this issue became.
Back to phones: We live in the age of multi-SIM carrier options (eSIM makes this even more convenient), cloud storage, syncing across devices and account based services: It never has been as convenient as it is today to just run multiple phones at once. Currently I have three active ones: The new Nothing Phone (3), Phone (2) as well as my Galaxy Fold 4. I haven’t decided whether I will sell the NP2 or not, but currently I don’t think I will. Since pretty much everything is synced, it almost doesn’t really matter which one I take.
You could just purchase both phones and simply take the one with you which currently fits your mood or which one you currently fancy more. Phone (3) is superior over (3a) Pro in pretty much all aspects, however the design is very nice and unique, the Glyph interface is different from the new matrix variant and, after having spent over a week with the new NP3, I habe to say I think the old light strip glyph interface was better.
If I could just purchase one phone, I would go for the new Phone (3) regardless: Since I don’t use a case, the Phone (3) offers a much nicer, sturdier build quality, better display and overall better performance.