o1bigtenor:
> Looking at ESP8266 [...]

Regarding the hardware side of this. I'm a little wary of all thoose
little "ready made" cards/modules, since when you need to put it to
use there is always the little detail about connectors and enclosures
and what environment you want to deploy it in, and you might find out
you still have to make a pcb for all connectors, interface components
and power handling --- so you might just as well do it from scratch.

Unless you need some more computing power and needs mcus/memory in bga
package (https://en.wikipedia.org/wiki/Ball_grid_array) which doesn't
lend itself to home manufactoring. For such cases I'd prefer SMARC:
https://sget.org/standards/smarc/
https://en.wikipedia.org/wiki/SMARC

Regards,
/Karl Hammar