Disable refresh after submit

There is a problem that refresh is too fast so some users didn’t see confirmation text after submit. So they fill form one more time and it makes a mess in submission limit, because of duplicates.

I thought I will fix it by redirecting users on the Thank you page after submit, but the refresh is too fast and earlier in order, so it does not have time to redirect.

Is there any option or snippet to disable refresh?
Thanks!