Stepper Motor Control??

DM drivers are definitely a step above TB drivers.

Given that prices have dropped quite a bit, you might also want to consider using closed loop stepper motors, as you can use the drivers error signal to stop things, should something go wrong, and you don't need to tune the system quite as conservatively, so you can push them that little bit harder to maximise travel speeds.

Controller wise, I personally wouldn't use Mach 3 for any new builds, unless you already had a controller or a license for it.
You can always start with something Arduino based, and leave enough room/cable in the control box to swap it later if needed.
My main concern with anything Arduino based, would be any pulse speed limitations. Microstepping and higher travel speeds can easily hit the limitation of lower performing controllers.

However, depending on budget, for simpler machines, I'd probably be looking at something like UCCNC ( https://cncdrive.com/ - their controllers are pretty good, and if it suits your requirements/budget, the AXBB-E is a nice package).
Centroid Acorn is worth a look as well - https://shopcentroidcnc.com/acorn-cnc-controller/ but it gets a bit spendy if you need any of the features not included with the Free software.
There are quite a few other options, but those are probably the most popular two, unless you go for something Mach 3/4 based, which if you did, there are quite a few other options, but I've not really kept up with them.

A note is generally Ethernet based controllers are more reliable.

Standalone wise, I'm not a fan of them for routers/mills, as I find them a bit limiting, however I do have a DDCV (I can never remember which version!) on a little Roland engraver, and it does the job.

All I can suggest, is spend some time looking at youtube videos of various controllers, and make sure any have any features that you require, but for a fairly basic router, most should be able to control it.