All iPads run the same iPadOS.
All current iPad models all either use the original, 1st or newer 2nd gen Apple Pencil.
( iPad 7th, 8th and 9th gen and iPad Mini 5 all use the original, 1st gen Apple Pencil )
( 2018, 2020 and the newest 2021 iPad Pro, iPad Mini 6 and 2020 iPad Air 4 models use the 2nd gen Apple Pencil )
So, iPads are more like cars, now.
You are paying for iPad optional features, now.
Do you want/need larger internal data storage space for data, like music. movies and photos/images and room for other types of data?
Do you need a larger or smaller iPad screen?
Do you/want/need higher color gamut display with Tru-tone room brightness calibration?
Do you need a larger screen with much more pixels that is much brighter, with a high resolution dymanimc ( XDR ) color gamut range?
Do you need/want an iPad model in a variety of colors?
Do you want/need a bonded, laminated display?
Do you want/need faster, more powerful internal CPU?
Do you want/need more internal processing RAM?
Do you want/need better iPad cameras?
Do you want/need better/more iPad speakers?
Do you want/need the improved, 2nd gen Apple Pencil?
Do you want/need to have the new Magic Keyboard portfolio for the 2018/2020 iPad Pro/iPad Air 4 models?
All of these options are what you need to decide if you really need, or not, and to decide to pay for accordingly.
The more iPad features you decide you need, the more you pay.
It all comes down to how much money you are willing to spend on iPads with additional, premium features.
You can now pretty much do everything on any current iPad model, now.
All current iPad models are sufficiently powerful enough, today, to do pretty much any task put to them now.
Tap the link below.
https://www.apple.com/ipad/compare/
Purchase the largest internal data storage capacity iPad model you can afford as no Apple mobile iOS/iPadOS devices have ANY internal expandable storage.