I had a similar post to the issue here (my post was mentioned earlier) and
@Atlantis_Court gave me the fix for it. I posted some more info over there but I thought I'd mention it here as well:
I looked a little further and saw, at least for me, when I had anti-aliasing on in the nvidia control panel, that's when the text in OBS was blurry. When I turned it off the text was fine.
I verified that the only settings that were different than the default on my end was the anti-aliasing was set to on and I had my max FPS set to 100. At this point my control panel is just set back to the default settings and it's seems to be working