Seconding Startech - I bought a DP to DVI-D adapter for my MacBook Pro and while it worked flawlessly with my PC, macOS was only showing me 1280x800 resolution instead of the monitor’s full 2560x1600 resolution. I found that under Windows on Bootcamp it fully worked on the same hardware so it was clearly a macOS thing.
Emailed their support about it and within a day, got a guy who immediately gave me very technical and specific advice and suggestions, clearly very experienced. We weren’t able to solve it (chalked it up to a weird macOS limitation and work gave me a different adapter that worked) but he was still incredibly helpful, and I’ll have confidence in buying from them in the future that their support should be excellent.
To add to this, I use an old iPad as a third monitor at work for Teams mostly. It’s 1024x768 which seems to be the minimum supported resolution for Teams (except for some applets) and I don’t need a good quality picture for Teams.
Unfortunately the app I’ve been using (TwomonUSB) seems to be no longer available for Windows download (CDN down), but this doesn’t affect me personally as I still have the setup anyway.