23" dado is probably beyond the capacity of most radial arm saws anyway. But used RA saws are a dime a dozen in the used tool market.

I'd use a router because I have 3 or 4 of them laying around.

https://woodworker.com/x5-12-radial-arm-saw-mssu-33-895X.asp?gclid=EAIaIQobChMIot7FmYyz4gIVGVYNCh2o7wCCEAMYAyAAEgKdRvD_BwE

Do a search, there is one listed at Home Depot too, and also Amazon.

None of those saws at the link have the capacity to plough a 23" dado though. To get a RA saw with that capacity, you're getting into industrial saw territory with 3 phase motors.

If I had one in my shop (I don't), I'd use a table saw with dado stack. So instead I'd use a router - ideally on a big table so you can set a fence and run multiple pieces at a fixed distance.

Track saw.

Thank you all for your replies. I had already saw cat's link online; it's discontinued. So I ended up using my router with a straightedge, it took longer, but I got it done.

Hmmm didnt see discontinued when I went looking. I guess, if thats the case, my big craftsman radial arm in my shop, will be babied a lot.. Its many years old, and used a whole lot. It is one of my favorite power tools.

Late to the party, but I'd use a dado blade, table saw, and sliding cross-cut table with stops where needed. Measure once, cut many times (with a stop and fence)