I've done a web search for the following error message that appears in your .xsession_errors log that you rightly included in your post:
RuntimeError: object at 0x7fd86c97dbc0 of type FolderColorMenu is not initialized
... and I've found the following discussion, also here in the Ubuntu MATE Community discussion forums, started by @tkn (thom), almost a year ago (in July 2022):
In that discussion, @thom ended up finding out that installing the package named folder-color solved the issue for him. You may also read the following related Bug report that he created in Launchpad, on 8 July 2022:
In that Bug report discussion, while trying to fetch "apport" information for the bug report, he found out that installing the folder-color package solved the issue related to the "FolderColorMenu is not initialized" error message:
So, @watchpocket , I suggest that you try to install the folder-color package and see if that also solves the issue for you, by running the following command:
I do already have the folder-color-caja package installed (described in Synaptic as "folder color for caja").
Also already installed is folder-color-common.
folder-color is described as "folder color for nautilus" and I do not have it installed.
But I think folder-color-common may be for the nautilus folder-color. So I will first install (the nautilus) folder-color to see if that helps.
Perhaps though, both (the nautilus) folder-color and (what may be 'the nautilus') folder-color-common should -- maybe -- both be removed. I'll have to experiment a bit here.
Stay tuned and thank you again. I'll report back asap.