The problem with RAMPs is that it has very little in the way of EMI protection. Perhaps for a foam cutter that is ok. For other uses, it is better to at least have low pass filters. Better yet, opto isolators.
I think you are talking about step sticks. That format is good up to about 1 Amp current drive though I would not want to hit 1A continuously given the tiny little heat sinks they come with. To go beyond that you will want external drivers. A step stick will drive Nema 17's ok. Maybe some Nema 23s if you don't need much power. If you go with stepsticks, you should get Trinamics (TMC2209, for example). They are quieter and handle higher current better.
Many 4 Axis Grbl boards are actually 3 Axis with another motor ganged with Y. Default Grbl is 3 Axis. Choose carefully. You need to find a code fork to do true 4 axis.
And, in the shameless promotion category, I make and sell a 5 axis grblHAL board. grblHAL is a 32-bit version of Grbl that runs on a number of different ARM microcontrollers (13 so far). My board is based on a Teensy 4.1 (600 MHz!). It has opto isolators for input and supports driving relay coils as well as SSRs. 0-10V spindle control. Screw terminals for more reliable connections. More info here.