So with the new update to CS:GO on 05/27/2020 they added panoramic backgrounds of in-game maps that you can choose from. I saw a steam guide that the guy broke down how to change it to whatever you want.

YOUTUBE VIDEO I USED:
https://www.youtube.com/watch?v=iiqNFMqszkk

YOUTUBE DOWNLOAD TOOL:
https://ymp4.download/youtube-mp4/

CREDIT TO ORIGINAL PERSON TO DISCOVER:
https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=2111177175
https://gtm.steamproxy.vip/id/GVoidV2