Its reached the point where you can't stop the spinners from cutting through your armour or bending your whole robot out of shape. The way forward now IMO is shock mounting your armour to lower the peak forces exerted by any weapons; see Beta as a great example.
Of course that has its own drawbacks and issues but even if you take an impact that lasts 0.1 seconds and turn it into 0.2 seconds you have still halved the peak force.

Regarding the question, I'd be tempted to have multiple armour pieces cut in Mild if you can't afford Hardox and just keep changing the panels. You only need it to last 3 minutes; that's still a LONG time with Carbide, but after that you can fix any damage. Just make sure you have spares!