While I can't answer this specifically I had a similar issue and the DeX ubuntu image had downloaded 3 times.. I found this using a paid storage analyser app I had (used google reward points to pay for it)
https://play.google.com/store/apps/details?id=com.mobile_infographics_tools.mydrive_ext
It's not a bad app tbh and will tell you in other what folders are filling up. No root access needed
Might help
Mine has seen pretty rugged use since it released. I've always had cases that protrude outwards a bit and they easily protect the scanner. Highly recommended. This blue one is nice. The screen protector scratches easily though. https://www.amazon.com/Samsung-i-Blason-Full-Body-Protector-Release/dp/B07GB6S1DZ?th=1
Galaxy Note 9 Screen Protector... https://www.amazon.com/dp/B07FXLSTJQ?ref=ppx_pop_mob_ap_share
They've replaced my protector twice, the second time because water got in due to a poor fit.
It's a great company and it works very well.
I've written four four page letters with inkredible pro, the main time i use the stylus. I don't notice any problems caused by the protector.
I use a spigen neo hybrid i got off mercari.
https://www.spigen.com/products/galaxy-note-9-case-neo-hybrid?variant=8837646516271
Just dropped the phone from two to three feet on a tile locker room floor today. No problems, it bounced a bit and is fine.
Definitely recommend the amfilm protector- I've used their iPad mini version too.