Thanks.
Also, I managed to recover my data because I had a backup from a week ago when it worked for the last time, and I also keep message export enabled by default and I'm exporting into text files. I managed to do a diff of the current data vs the data in my profile, trim the exported text files and import them.. I may have lost some avatar change history since it doesn't get imported there I think, but at the same time I lost no history as far as text goes.
There you have it. Not awesome libmdbx, not autobackups but good ol' ImportTXT and messageexport saved my history...
This is why I'm reluctant to allow their deprecation until something that works "the same way" exists , @Ghazan
DB autobackups does not work properly either since a few days ago as well which I didn't notice (the db size is about 10-15 MB less than the actual db I'm using and when you try opening it, it just gets truncated to 1MB on open. Trying to use importer just says error.
EDIT:
Since I had to troubleshoot and repair the ImportTXT template for "MsgExport" data format, I'm submitting it as a pull request on github in case anyone else wants to use it; so they don't have to debug a gigantic regex too :p