Your log seems to only be full of bug 1857392. It's quite unusual to see that message every 10-15 seconds so I wonder what's triggering it. Any repeating action like that can cause leaks too.
I can also see at least two leak fixes that haven't made it into 20.04 yet: bug 1876641 and bug 1962565. So the next thing you should try is disabling the Ubuntu Dock extension and then log in again.
Your log seems to only be full of bug 1857392. It's quite unusual to see that message every 10-15 seconds so I wonder what's triggering it. Any repeating action like that can cause leaks too.
I can also see at least two leak fixes that haven't made it into 20.04 yet: bug 1876641 and bug 1962565. So the next thing you should try is disabling the Ubuntu Dock extension and then log in again.