MAC Client FPS issues after patch 8.23

After updating to patch 8.23 I have no been able to play league properly since. My FPS literally crashes to 10FPS in every team fight. I played ranked from season 4 on the same MAC, no issues, nothing different apart from the patch and now unable to play. Anyone else experience this? I’ve been in contact with riot who have no idea what’s going on. First it was McAfee, they said that was the problem. I removed it. Still no better. They then said it was that I had external monitors. They said unplug them. But why should I unplug monitors I’ve never had issues with. Anyways to humour them I did. Still the same problem. I don’t know what to do. And no, I am not buying a secondary computer. I use this for my home digital design business and uni course. There is no physical or technological need to purchase a windows pc. I want the Mac client fixed!!!!! It’s been in beta for 4 bloody years!