I should stress that although Lynx did get through 3mm steel, it wasn't by much. Just a small hole on the underside. That's not to belittle Lynx's achievements but just so you're not writing off 3mm steel as armour. It will still stand up against a lot of what is out there.

I also don't think you need an overkill wedge/box to beat a spinner. My beetle Flatulence is the one with the aforementioned 3mm steel. It's all done at an angle due to it being part of a flipper blade and is a great source of protection while also having offensive capabilities. At the Scotland Iron Games event, it took a bit of a beating from Eggbeater in the final but once I was able to keep the front end pointed at his weapon, I was able to take the hits, stop the beater from rotating and then take control of the fight. In a match against Spin Cycle, the flipper blade took an impact but the force caused more damage to Spin Cycle and Flatulence went on to win the fight. So it is possible to defend against, and cause damage to, them with something other than a brick. Flatulence isn't even that expensive but has been through about fifteen battles at various events and only needs a bit of cosmetic TLC to get it ready for November.

As for entangling spinners, an idea came to me today. At work we have protective kevlar sleeves we can wear as part of our PPE. You can put them on your arms and run a brand new stanley knife blade down it and it doesn't cut it or get through to your skin. If you get hold of something like that, you could put it between a pair of arms or claws and drive that into spinners. Not saying that discs won't tear it up, but if it survives the impacts, it would take a lot of energy out of the hit, allowing you to snag up the spinning blade and let you dictate the fight. The benefit of it being attached to your robot is that it won't (or shouldn't) get tangled up, letting you back away and reuse it as an attack while not violating the entanglement rules