Gah, unfortunately we may be out of luck with brew and ollama, judging on the mac folks’ experience: Maybe try the direct installer in this case and fiddle with the path and whatnot till it works. Sorry! I don’t have a strong GPU so I never worried about it running on the CPU.
https://www.reddit.com/r/ollama/comments/1h7grjl/m3_macbook_pro_18gb_not_using_gpu/