I installed OBS 27.2.64 yesterday because when I joined a Teams meeting as a guest it refused to allow me to blur my background (I could 'switch it on, but couldn't get it to stick). Being able to blur/obscure my background is a fundamental requirement and should be built into all services providing Webcam meetings by default; I'm joining a meeting not inviting people into my house. I don't know why Teams failed in that regard, and that's a separate issue, but it did set me on the path to OBS Studio.
I had hoped to be able to use OBS Studio to provide a virtual background, which failed, so I tried XSplit. That's another separate issue, but delayed me slightly because XSplit apparently set itself to start with Windows and, I think, initially prevented Teams from recognising the OBS Virtual Camera.
I did, however, ultimately succeed (which I hope is good news for you). Having started a Teams meeting, I clicked the ... at the bottom-left of the window, the selected Switch camera. It took two attempts, but it did work.
The quickest test for you would be to try the Switch camera option, and if that doesn't work, update OBS then try again. Whether that works or not, it would be a good thing if you come back in and let people know how it all turned out.
I hope this helps.
