Limiting Gmail downloads to Mac Mail

I use Gmail with Mac Mail via IMAP, and I have many years worth of Gmail in my archives. Do you know of a way to limit the amount of time that Gmail stays on my Mac? I'd love to have it purge after somewhere between a month and six months. For anything older, I could go to Gmail on the web. Note: I'm running Big Sur. I only picked Mojave because I had to pick something and Big Sur wasn't an option. Thanks!