Since your experience is not typical you need to supply additional information.
1. What computer are you using
2. What extensions have you installed
3. Do the problems occur if you boot into safe mode.
4. Any specific Yahoo function that fails? Mail, website?
5. Don't understand "but all my websites are on Safari". Websites are accessible by any HTML browser that you chose.
I'm on Monterey and have no problems so first guess is that the problem is an issue on your Mac.
1.
iMac (Retina 5k, 27 inch, late 2015),
Processor 3.2 GHz Quad-Core Intel Core i5,
Memory 8 GB 1867 MHz DDR3,
Graphics AMD Radeon R9 M380 2 GB
2. I don't think I have any extensions maybe Grammarly, and capital one shopping.
3. I haven't done a safe mode boot.
4. My mail and then it just slows everything down and a notification pops up by the tab saying something about this site is using a lot of memory to close it.
5. I have lots of sites saved in Safari that I don't know how to have on Chrome.