You didn't mention you already owned a 1st version Apple Pencil.
All Apple Pencils are optional purchase AND the 1st gen Apple Pencil is NOT compatible with any of the 2018 or 2020 iPad Pro models.
I thought 125 GBs was enough space, too, but just purchase another 4-year old 2016, 12.9 inch iPad Pro for a very good price and that one is a 256 GBs storage model with WiFi and cellular data.
A 125 GBs storage model iPad has only a practical, usable internal storage space of 111-112 GB after formatting and installation of iPadOS.
I got my original 128 GBs iPad Pro down to approx. 25 GBs of internal data storage left.
I used 87 GBs worth of internal data storage space with apps and app data, eMagazines, videos, images and music.
Since you do not seem keen to want to purchase a more expensive Apple Pencil 2, and you already own an Apple Pencil 1st generation, maybe you should consider the 2019, 10.5 inch screen iPad Air 3 and consider purchasing this version in a 256 GBs storage version, instead.
I feel the more internal and more direct and instant internal data storage space you can purchase in an iPad, the better!
Having to transfer data back and forth from a full computer or from other online data backup and storage services can be a pain to constantly be doing all the time.
I like having instant data access from my iPads.
Best of Luck to You!