A few things to try, which may or may not help in this undetailed issue-statement
could be re-start in Safe mode; that may take up to 15+ minutes. It checks macOS
and can repair some items, without telling you what they may be. Read carefully.
• How to use Safe mode on your Mac - Apple Support
https://support.apple.com/en-us/HT201262
Another, may be to restart in Recovery and use the disk utility found there to repair
your Mac storage. - Or - if your Mac is an Intel-or-Silicon product, try hold 'Opt' key
on restart and select from disk items that should appear on the screen.. There may
a 'Recovery-named one' marked specific to your Mac and its present startup system.
You could try and use that, to gain access to a recovery independent that is unmounted
and not part of the running macOS. This can work; to repair things and to avoid reinstall.
I'd try Safe mode first; you'd login with Admin password and a red letter Safe mode start
wording will appear in upper right margin. Generally the screen may blink and act slow.
When it's done or you find little else to do there, restart normally. Give this about an hour.
This may self-fix any of the underlying causes of symptoms. ~Or, try another browser. If you
have one that Gmail can use; some may not be a good match; or other issues are at work.
PS: if you haven't set up Apple Mail, or have issues with Google Mail a few replies that
may or may not help (with links) are in this thread. "how can i receive email in Mac"
Since you've not detailed anything helpful, I'll leave this here.