Greetings,
Its a long shot, but please compare your S/N and see if your camera is affected by this possible recall. It ends in 2 weeks.
Canon Support | Service Notice: EOS 70D: Error 70 or Error 80 | Canon U.S.A., Inc.
While it initially presented as a lens communication faliure, or unresponsive body, it was later determined to be caused by a defective mainboard PCB. Your issue might be completely unrelated or it might be manifesting itself by the failing top screen display and missing information in the viewfinder. Power related issue, etc. What you are describing does not sound like a corrupt settings problem, but you can also try resetting the camera to defaults as well.
I would test further by removing the lens and card, and also confirm your battery is of known good quality and condition. If you have more than one battery, test using both. If the behavior continues, and the camera falls within the affected serial number range, I would contact Canon support and arrange to have your camera inspected. The inspection is free. If your serial number is affected, you'll need to do this as soon as possible. If not, then you may have just run into some bad luck.
~Rick
Bay Area - CA
~R5 C (1.0.6.1) ~RF Trinity, ~RF 100 Macro, ~RF 100~400, ~RF 100~500, +RF 1.4x TC, +Canon Control Ring, BG-R10, 430EX III-RT ~DxO PhotoLab Elite ~DaVinci Resolve ~Windows11 Pro ~ImageClass MF644Cdw/MF656Cdw ~Pixel 8
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