I was busy, just looked at the clip now. For 720p60 it doesn't look that terrible, but when watching in fullscreen - yeah, the large single-colored areas look blurry. That's not uncommon though, many streamers especially on Twtich (non-partnered / partnered / affiliate) don't have good stream quality, mostly because of hardware limitations.
But for high bitrate (6000 kbps) and slower CPU preset like fast / medium that doesn't seem quite right...
I was relatively small content creator quite a while ago, currently I'm not making any content or streaming. But not so long ago I have experimented with OBS streaming settings (just out of curiosity) to try and see what are the best settings, suitable for me and to understand what works better in certain scenarios.
I have 6700K @ 4.40GHz & 1070 Ti, the quality on the most popular games like CS:GO, Minecraft, ETS 2, etc. wasn't good at all, even the crosshairs / details / distant objects were washed out and very blurry. I wasn't able to find what could be causing blurriness and poor quality especially for my setup and streaming settings, while streamers (let's say on Twitch) have great quality with very low bitrates and middle-range PCs.
So, generally I know which settings could work "okay" for me and what to recommend to someone who isn't very familiar with these things, but unfortunately I can't say for sure what could be causing blurriness and drop in quality in this particular case. When watching in non-fullscreen mode it looks better and I'd say it's acceptable to some extent...