At least since COVID lockdown, there’s no reason to read on a smartphone. If one is not commuting and traveling around, portability is not a factor and it’s an inferior experience to iPad mini or eReader, just because text layout is cramped (I do use a fairly small font).
When I was more mobile, I mostly just read on iPad mini and iPhone, Kindle was last in line. But now it is more 50/50 mini and Kindle (arbitrary split is ‘immersion reading’ on mini, everything else on Kindle).
If I didn’t have the mini, I’d probably have to get one. 10”+ tablets are too big, smartphones too small