@Matt621,
While you’re welcome to use whatever OS you want for whatever reasons you’d like, the truth is that older OS are not receiving browser updates (not just from us but from most browsers) any more, which means (as you likely already know) that they are missing important security and bug fixes.
I’m not claiming that your using Win7 is the cause of this particular issue, but I just want to note that there will likely come a time where you encounter an issue in Brave browser (or another browser) that we may not be able to resolve.
All that being said, it sounds like you both may need to clear cache/browsing data for all Google related sites (you may need to clear all of it in general but I would start with those sites) and see if that clears up the issue. @Letstalk asked above why it’s working on a guest account and not your normal one as they likely share different user data and the issue is only present in one of them.
You can try clearing this data by going to brave://settings/content/ in Brave, searching for “google” and deleting the cache/site data from there. Let me know if this works for you.