Hi,
I only did a search on "TMC2209 steps" and i found results, take a look at this link, there is all details about this stepper motor driver:
TMC2209
So, you can even make it to works in fullstep.
But the couple will be more high, so, put end stop contacts, unless you want a broken machine.
The "sensorless" feature is never the best solution, you can imagine what the power signal on a motor can do on the other signal wires.
So on the UART or TX/RX wires, no matter the type of communication, emmm

I have CNC milling machines it's not the same than a 3D Printer.
EDIT: At my idea you have a lot of cheap cards to drive the Nemas, why you try to do your own one more ? For a CNC lathe you can even use an arduino with GRBL. For a lathe with stepper motors at 2A you'll certainly not do steel or aluminium, there are a lot of examples on the web, unfortunately all my links i have are in French.
Plus on a Wemos or any ESP8266 cards the Wifi needs MCU cycles to manage the Wifi, it's not really good idea to use them to drive a CNC who need a constant flow of the GCode on the machine.
As far as i know at all time i driven my CNCs i never have really often lost step. It was rare or most of time a collision between the tool and an other part of the piece. But i always use the machine under the max of couple or their max speed on my different motors. The smallest works with GRBL.
To be honest the ESPxx are really not the good MCU to drive a CNC, maybe not enough GPIO, a CNC need several sensors Urgency Stop, end stop, etc. on a milling CNC it's worst, the Wifi need MCU Cycles, you can not stop the loop or make her too busy without a reboot, because the Wifi will stop it through the watchdog.
Try to make a loop too busy and you'll seen your Wemos rebooting often.