Tubeless tire leaks from valve

Hi again. I've got most of the leaks sorted in my gravel bike's new tubeless tires, but they're still going flat, now in about 5 minutes. I did the soap test to determine where the leaks are, and the only leaks I can see are right at the base of the valve stem.

Searching for this online, most answers were "it's the tape". But these wheels are only about 1 year old and the hole at the valve looks clean / flat to me.

I am using Stans valves and have about 4oz of sealant in there right now, if that helps.

Is there any way to resolve this, short of completely re-taping the rim?

Thanks!