I hate to say this, but it seems like a pretty clear case of using the wrong tool for the job.
There's no conceivable reason to cut something this simple on a large-format CNC mill. It's literally just a couple of straight cuts. It's not going to be faster (not with standard endmills), not going to be easier, and it's not going to be cheaper unless you're making them by the thousands.
You can likely buy S4S lumber for less than an oversized sheet of furniture-grade 1" plywood.
If the machine is available and it’s a hobby project it’s ok, but you’re right this is not a cheap or easy way to do it.
But as a mechanical engineer, the whole project is such a “software” approach to me, starting from turning the selected tool into a requirement to use. Then, rather than just powering through in solidworks for a one-off design, the author spends a lot of time looking for automation tools like they are a library, points out this approach feels like coding in rust, gives up, and even blogs about it.
We grew with overbuilt furniture, trailers, radio masts, gas fittings, plumbing, etc. that my father built. A whole lot of knitted jumpers, wool socks, bed covers, etc. from my mother and the aunts with a freezer full of home cooked meals scaled for shearing teams and put away for later.
Most of that carries on, and we've got good relations with a slew of people that are solid craftspeople who put their best work in galleries for the extra big bucks.
The good stuff is as accessible to us normies as good software is to the HN crowd .. it costs less or nothing if you're in the maker circles swapping food, yarns, and other goods.
FWiW I was a silent partner and occasional assistant in a glass studio / wood shop for two decades, that helps - that was some money (way back when you could get a lot of land for a lot less than today) and a lot of sweat equity modifying buildings and landscaping, etc.
There's no conceivable reason to cut something this simple on a large-format CNC mill. It's literally just a couple of straight cuts. It's not going to be faster (not with standard endmills), not going to be easier, and it's not going to be cheaper unless you're making them by the thousands.
You can likely buy S4S lumber for less than an oversized sheet of furniture-grade 1" plywood.