With Block very likely scams automatically turned on in Settings, messages that are almost certainly scams skip quarantine. They go straight to Blocked instead of quarantine. You can still find them there.
Only messages that are both very risky and judged with high confidence are blocked; anything less certain still goes to quarantine for you to review.
Blocking senders too: with Also block those numbers on this phone on, blocked numbers are also added to Android's own block list, so their calls are blocked as well.
Nothing blocked is deleted straight away: check Quarantine → Blocked now and then. If a genuine message was blocked, release it there.