I would recommend deleting the SHQ Monday Mods_Sept2019 and Feb2020 versions after you've gotten the latest one installed and working.
in the Sept2019 modset, we had
Please delete those, as they are no longer in our modset, even the Sept2020 one.
Also, when mod makers update their mods, they sometimes rename them and upload. In this case, the old version is not deleted and there are multiple versions of the same map.
I would recommend you go to the file directory where the addons are and remove them.
For me, the directory is Steamapps\common\Arma 3\!Workshop
In my directory, I see duplicates for Isla Duala, Lingor-Dingor and several others. You might want to consider deleting the old versions. If you delete all versions of that particular mod, it will redownload or you might have to manually redownload the latest one. But you'll be able to save more disk space that way.
If you're uncomfortable about deleting something in that directory, post a screenshot of that directory and I can help you pick what should be deleted.