Usual preface, I’m with PreciseBits so while I try to only post general information take everything I say with the understanding that I have a bias.
While I don’t have any experience with drill mills, I can say that is a low number of holes to get in a standard carbide drill. We normally see about double that in FR4 which is quite a bit tougher on carbide.
I guess I’m going to be the odd man out here as I don’t see the real issue being your RPM. It might not be ideal but I don’t think it’s the primary issue for the tool life. Barring a lot of runout, the issue I see is that you are running much too low of a chipload to keep from burning up the tool. There’s lots of explanations why (heat transfer, rubbing, cleaving size, etc) but at the end of the day lower chip loads produce more heat and reduce tool life. Enough heat and you’ll actually leach the cobalt from the tool and greatly decrease tool life.
Without specific knowledge of the bit being used what I would do is run some test cuts. Basically run a set of holes and on each one increase the feed by 5IPM. Since you are running a multi-material cut look for where one of the materials start to give you a bad cut or you reach a setup limit. Back it off 10% to allow for tool wear and you should have a decent setup. I’d expect you to have no issue and much better tool life around 66IPM. Again though, I’m not familiar with the geometry of that specific tool or potential runout so I’d test for it.
TiAlN coatings might help a little as it can add a harder layer and smooth out the grinding marks. But you won’t be able to form the oxide layer as the temperature required is too high for wood. If you are able to find them, better coatings to try to preserve an edge with a low chipload in softer materials would be ZrN or some of the DLC coatings that don’t effect the cobalt binder.
Keep in mind though that all coatings are increasing the thickness of the edge of the tool (you’re coating ALL of the tool). This is functionally slightly dulling it in exchange for a higher wear resistant surface.
In my opinion, all of the coatings won’t give you as much extra life as running a higher chipload.