I've bought around 6 Nema23 motors with drivers and 2 Nema34 motors with drivers from Ali, and they all work.
The "closed loop steppers" are significantly quieter in operation, and well worth the price difference.
In the bigger CO2 lasers there is often a small timing belt on the motor to an intermediate axle, and then a cut open timing belt to move the gantry, and it usually adds a extra gear reducion of 1:3. These intermediate axles can be bought as spare parts for reasonable prices. I'm not sure if plastic or rubber timing belts are the best option for a plasma cutter. You may want to consider a regular bycicle chain, but don't make the sprockets too small, or you will get into trouble because those sprockets are polygons (with each teeth) and not "circles".
It's probably a good idea to use these.
Stepper motors loose torque at High RPM, (This gets serious above 600RPM, depending on power supply voltage) but with the 1:3 reduction you need less torque from the motor. Result is higher resolution, and more freedom in choosing the diameter of the pulley's.
If you want to go LinuxCNC. I guggest to add a MESA FPGA card. I think they cost around EUR150, but the extra reliability is probably well worth it.
If you want to go cheap...
I've burned a Grbl clone for an STM32 into a "Blue Pill" and added some good old 74LS line driver chips to drive the opto couplers in the stepper motor drivers. Soldered it all on Matrix board.
I use bCNC for driving Grbl. It's a simple program (for today's standards) but it does get the job done, and it has some nice features for post processing your CAD files. It can add stuff as tool offsets, lead in and out.
It also has special features for cutting plotters, which add "swirls" in tight corners.
I do not know of special features for plasma cutters in bCNC. Would any be needed?
bCNC is also written in Python, and there are some 20+ plugins such as spirograph generators, puzzle pieces and such. You can study those to write your own plugins for special functions if needed.
bCNC also has a Z-height "probe" function built in.
Original function for this is for PCB milling, to take of the copper, and leave the glass alone, but the same feature can also be used for your probe height compensation of course.