I’m used to cutting PMMA (plexiglass) and I gained my experience the hard way with broken bits and bald spots on my head. Cut speed affects results. The math is how much material needs to be removed per bite (called chips) to keep things cool so you don’t melt the material and create swarf which will gum up your bit.
Linear speed and RPM will control how much bite your bit will cut. No enough movement or too much RPM and heat builds up on the bit because your chip size is too small. Too much movement or slow RPM and your are biting more then you should.
Double flute vs. single effectively doubles your RPMs reducing your chip size if you don’t increase your rate of travel. It took me a while to really get it in my head that I wasn’t going fast enough. (I had a 10k RPM router and double flutes.)
Another thing I might suggest if you are cutting through holes, just cut the outline of the hole. If you are cutting pockets (as in your picture) it’s gonna take a while.
Grab a test piece and start playing with the numbers (speed & RPM) until you have problems. Use a notebook and record results, you will appreciate it in the future. Make note of the Router, Speed setting, Material, Bit size and type, and even it’s sharpness. Wood you will want to note the season or humidity/moisture level.