Hi Dan
Sorry for the delay, but life as usual gets in the way!
I may be getting somewhere in narrowing down the issue.
I use a 65” TV as my main monitor and that was fine being fed from an intel 27” iMac.
Trying several different scenarios it seems that the TV is the issue probably related to graphics drivers.
1. Just TV - no text below 8mm.
2. Just 1080P 24” monitor - text available at all sizes.
3. Monitor only connected - text fine. Then plug TV in and text visible on either screen if I move the Fusion window from one to another.
4. Disconnect monitor and text still visible and adjustable on TV.
5. Restart Fusion with either scenario 3 or 4 and text disappears below 8mm again.
6. Disconnect TV and do not restart Fusion, text is not visible below 8mm on the monitor until a Fusion restart, then it’s fine again.
I have tried multiple HDMI cables and swapped USB-C with HDMI on the Mac and this makes no difference the results are exactly the same.
Hoping it may help I’ve included logs where only the TV or monitor are plugged in.
Fusion is the only program I’m having issues with and was present in Ventura and on Sonoma which I’ve now done a clean install of with Fusion being the only program installed!