500 interval server error and saturated database

Since upgrading to version 2.9.0 (build 5150) 240687 I have only encountered problems.
In addition to my Multiple accounts problem I have unsynchronized files with a message The server replied “500 Internal Server Error” to "PUT or The server replied" 500 Internal Server Error “to” MKCOL

My database is also filling up in a weird way!

Where does the problem come from?

I use Owncloud 2.9.0 (build 5150) 240687
Ordinateur Mac Os 10.15.7
Serveur Ovh Mutualisé php 7.3
MYSQL v.5.6