It may not be this but try checking Lenovo’s Vantage software, if you even have it installed, and look for “Network Boost” or something similar sounding. It might be enabled by default and disabling it might help you.

I helped a friend diagnose a similar issue. It was a Lenovo laptop that of course came with Vantage preinstalled. And the issue was similar in the way that he would be on a Discord call with me and everything was fine with the audio quality and ping until he would start streaming an online game, then his audio and stream would stutter heavily and he would see high ping on Discord. I don’t quite remember all the details to be sure it was the same as your case. At least for his case, disabling the Network Boost option solved the issue.

I believe that the idea of that Network Boost is that you can give higher network priority to game data packets and everything else comes later, when most default network protocols give audio and video higher priority usually. So at least in my friend’s case the game would see an unperceptively small ping boost while Discord would just struggle to work.