You need different software for different tasks.
GRBL is only the part that lives in a microcontroller. It receives test strings with G-code, and it translates this to stepper motor timing pulses. A few years ago I flashed it in a "Blue Pill", but in the meantime GRBL has moved on. Back then the atmega328 it was originally designed on was reaching it's limit and there were a lot of forks to 32bit (mostly ARM-cortex) controllers, but also others such as ESP32. A few years ago a lot of these projects have come together again in the GRBLhal project on github.
In the mean time my "Blue Pill" is also deprecated, but as a test I flashed GRBL into a WeAct "Black Pill (with STM32F411) and I've seen the stepper motor pulses on my scope, but not attached to hardware yet.
Personally I do not trust WiFi much for CNC control, but the Teensy 4.1 seems quite attractive because of it's wired Ethernet, which is by definition gavanically isolated from your PC. There are also break out boards on Tindy (and PCB design files on github) with buffers and screw connectors for the Teensy.
The next software piece you need is for the PC part. I use bCNC on my Linux box myself. It has nice extra functions such as import of simple DXF files and then adding multiple passes and tabs, and you can also import multiple files and nest them, but this is all manual work. bCNC can also do Z-axis probing for PCB milling to get a uniform depth even with a slightly bent PCB.
But programs to control GRBL typically have G-code as input. The most usual workflow is to first design a PCB, then create a set of Gerber files (because it's a standardized format) and then use programs such as coppercam (commercial) or FlatCAM (Open Source) to translate the Gerber files into G-code.
I have not (yet) milled a PCB myself, but I do know that GRBL itself is quite reasonable.
Quite a long time ago I bought a Beaglebone Black to run Machinekit (a fork of LinuxCNC), but the GUI update rate was quite slow over SSH (about 1 frame per second). So I tried GRBL and bCNC and it works good enough for me and I never tried another combination.