No way to check file integrity... in 2021?

[MichaMMA]

at least it is an assumption that the game do a full redownload as the mentioned reason.

Download issues can have different reasons and there exists an FAQ.

For Steam verify I recommend topics like:

Steam - Verify Integrity of Game Files Deletes All Content

Usings Steams ‘Validate File Integrity’ option deletes all simulator content without warning. Typically when using this option on other games in Steam, it seems to evaluate game files and re-aquires the ones that are damaged. Because this behaves differently for MSFS it catches users off guard on a regular basis. This is problematic as it forces unsuspecting users to require the simulator content, and may lead to them encountering the Only 2 aircraft bug. This can be especially upsetting for …