Problem with Safari on Banking and Payment sites

Over the past few months I've noticed problems with Safari on my online banking app (USAA) and with online payment apps for certain merchants (Western Disposal and others). I'm using Safari 16.0 on Big Sur 11.7. With the banking app, everything works fine except it hangs up after I start the online bill pay process. With the payment apps it hangs when I'm filling out info like credit card number. When I switch to Firefox I have no problems. The bank tech support suggested I try another browser, but didn't say they don't specifically support Safari. I never had this problem in the past.

Has Safari changed something internal such that it conflicts with these sites, has something changed in the community such that developers are moving away from Safari or ?

thank you