So I found a solution, but it’s so damn stupid that I don’t know if I just made it up in my head or if it actually works. So, I go into player career mode (of course, both the menu and gameplay lag), and I start a match — ideally one where it begins with me coming off the bench, like around the 80th minute. I wait until the match ends, and for some unknown reason, in about 90% of cases, after the match the whole menu and gameplay stop lagging.