I have always thought that iPad is useless for me when there's a laptop and phone but after a whole day of using my laptop I just switch to my phone. The screen is not small (at around 6 inches), but it's of course not enough for comfortable reading.
I know very little about iPads, to be honest, so the number of models available is frustrating. Overall, it seems that iPad 9th gen and iPad Air 5th gen are of great value and I definitely don't need the more expensive models. That said, even between these two models there is a huge price difference.
Which model would you personally buy now?
To be frank though, so are AMZN Fire Tablets and even though they have some annoyances the price is really right. There is some "reality distortion field" such that people wonder "where did all the Android tablets go?" and never see they are hidden in plain site.
Also iOS' builtin text-to-speech produces almost audiobook qaulity narration, but it's annoying to use with PDFs as it's hard to tell it where to start to read from, it works much better with epub format.
Frankly just go to an Apple Store and try them out, then buy a used iPad of that size for a fraction of the price, and none of the ecological impact.