You can set a personal rule in Ublock origin to block these sign in with Google pop-ups.

https://www.reddit.com/r/uBlockOrigin/wiki/solutions/#wiki_g...

there are usage limits preventing you from running it 24/7 on all subscriptions tiers

This bolster's OP's point, to an extent

Try disabling CSP for the page

Firefox and my ISP have deemed this site to contain malware...