I can't even use ViaBTC anymore: they're instantly full every hour, and I don't even get to see a number larger than 0 anymore.
You don't have hit refresh at xx:00.
The moment your clock (assuming laptop or desktop here) shows 1 second you hit free submission.
That's the way I managed to accelerate like 4 tx Monday to Wednesday!
What's really annoying is that Viabtc right now helps even with ordinals inscriptions, this guy is taking advantage of this and I assume he is using a bot for it:
https://ordiscan.com/address/bc1q7357af8tkcttej0cqmqzvhfja9ey63pzpd74qr/activity