I've currently got a Samsung S10 which I has everything I need, plus more over the current flagships like triple camera (some only have dual), expandable storage and the elusive headphone jack.
However, the only thing that bugs me about Android phone is how poorly the battery holds up/amount of major software updates. I believe I've just received my 3rd and last one. iPhones get way more updates and anecdotally hold up better.
So I'm considering switching to Apple after over a decade with Samsung going back to the S2. After they've removed expandable storage and the headphone jack, I don't think there is enough separating flagship androids vs iPhones anymore.
I know that mid range Android phones still have some of the above features but I don't think they have much longevity considering I want my next phone to last 4-5+ years.
TDLR: My S10 is 3 years old, looking for strangers to convince me to suck it up, get a new battery and hold onto my phone for another year (to avoid dropping 1.5k on an iPhone)
Why would you not trade in on the S21 FE deal for ~$500.