if you are comfortable with electronics check out bart dring's esp32 port and board for grbl. You can get the board on tindie or make it yourself. it can do wireless and it also has a few extra pins available. The esp32 has a ton of resources and is much much faster than an 8 bit arduino. You also can run it directly over usb if you don't want to use the wifi/bluetooth.

I wanted to try out g2core but the learning curve is very high for a DIY build (I was going to make my own board).

Grbl is great and very well supported with plenty of tutorials available. Check out universal gcode platform and bcnc which are used to drive grbl and feed it g-code. They also do things like run probing routines.