TeamViewer on Mac 10.10.5 Yosemite can no longer control any other computer

I have been testing over the last two days for hours, and there is no more any way for my main computer, an iMac 2010 running OS X 10.10.5 Yosemite, to control any other computer any more.

Either it gets the 5 minute time-out warning, or else it just can't connect.

Reason being that the last TeamViewer release for Yosemite 10.10 was TV v13.2.75535 or 75536 released on Apr 23 2019. (note that the program shows its final version node as 75535 in some places, and 75536 in the About TeamViewer Apple Menu info window when running the program).

When I try to connect to a computer running any TeamViewer QuickSupport release of version 13 or less, I am given a warning that program will timeout/stop after 5 minutes since the QS version is too old. But when I update the remote computer to TV QS version 14, now TeamViewer (full) on my Mac states it cannot control a newer remote QS version. So it asks if I wish to update my local FULL TeamViewer (from v13 to 14). I know it will fail, but click yes install anyway. It downloads v 14, then insists that there is no compatible computer hard drive.

So I am totally stuck, I have the latest possible for Yosemite, but it won't any longer connect to anyone for more than 5 minutes (seemed less than that in my testing...).

Since the QS must be running version 14 to avoid the 5-minute timeout limitation, and since my iMac Yosemite can only run last final release of version 13, and since TeamViewer 'rule' is that the TeamViewer Full (controlling side) must be at same or higher version than QS side -- well I can no longer make it work.

Very sad about this. Even though I only use it a few times a year to help family or friend diagnose issues, or give a little tutorial, but wont be able to any more.

Can you please suggest some method or alternative which still supports Yosemite?

Thank you.