Second Streaming Monitor to go with Main gaming computer

I have seen a number of multi monitor setups in my time and have never seen an issue with pairs of disssimilar monitors.
Windows lets you set the display frequency on each monitor seperately
Issues with multimonitor setups usually originate with the GPU, but you have not stated what yours is so whatever, I probably have not played with your specific model anyway.
Moving windows from one monitor to the other may be fun as the DPI are so different, but that would be only an amusing inconvienience.
Worst case, you could drop your 2k display to the same 60 hz as the 1080p monitor / turn off the 2nd monitor if it is affecting the display while you are running at 165 hz

Thanks a bunch for the prompt response. My GPU is a 1080ti so I would assume I’m good to go. And well that makes sense about the DPI, didn’t think about that but I guess it would be just fine because I play at a low DPI for my games and I do like my mouse to be a little bit quicker when browsing.

so since I’ve never used a second monitor before. Would I be able to play games on full screen and how would I scroll to other monitor? Would it ever go to second monitor when playing when accidentally moving mouse too far to the right or left depending where second monitor is?

It depends on the game. Typically a full screen game will display on your primary display and leave whatever is on your 2nd display the way that it is. Nice for email.
If you want to pause the game to reply to an email, that can be fun. Usually the full screen swtiches to a windowed display, then you have to figure out how to get it back to full screen (F12 or Alt Enter)

Thanks Sean! You have been of great help! Appreciate it.