Fonts not activating in Indesign - cannot manage fonts in CC

Hi, I'm using an older iMac (2017) OS High Sierra. I've had recent problems with Creative Cloud not automatically activating fonts and I was manually activating them in the font manager within CC. However, I now can't open that either (spinning wheel). I uninstalled creative cloud and re-installed via Adobe support, but that hasn't fixed the problem. I've updated all software as far as I can take it on this mac. Please don't suggest buying new hardware - it's not an option!

I know others are experiencing this, but has anyone found a solution? I was on a chat with Adobe for over an hour yesterday and I found it quite hard to follow what they were asking me to do (see copied and pasted instructions below): I couldn't get anywhere with this as I didn't receive the file over email.  Anyone got any suggestions? Thanks
1 - Turn off auto-update in Creative Cloud.
2 - Close all the processes of CCDA (Core sync, Creative Cloud) from the activity monitor.
3 - Navigate to “/Applications/Utilities/Adobe Sync/CoreSync” and take the backup "Core Sync.app". Delete “Core Sync.app” inside the folder.
4 - Download the CoreSync.DMG file on the user's machine and double-click on it.
5 - Copy the “Core Sync.app” and paste “/Applications/Utilities/Adobe Sync/CoreSync” inside folders.
6 - Relaunch CCDA, and it will ask to open the Coresync service. Please click on yes.
7 - Fonts should start getting reactivated automatically in the fonts panel in CCDA.
I have sent you the file over the email.