I've checked in with Google support and got transferred twice all the way to a specialist and after much probing I got them to make the following clear statement:

"Google Workspace Support: ...if there is no limit set per Shared Drive and a single Shared Drive is not reaching the item cap of 400,000 even if the files stored is too large it will still not trigger a limit until it reaches the 400,000 item cap."

In other words, you can see your pooled storage being exceeded but shared drive storage won't cause any problems unless the admin set a shared drive storage limit or if you reach the 400,000 file count cap. So without any storage limit, you only have the file count cap and the folder ne sting limits to worry about.

They also made references trying to curb abuse and I think the way they are showing the storage limit in Google Workspace is designed to push people to limit their storage usage. it seems to work based on all the Reddit threads I've seen about this.

I hope this clams some people's nerves. Continue enjoying unlimited shared drive storage :)