Digispark Micro (ATTINY85) not working on Macbook Pro 2016
Digisparks are known to have problems with USB3 ports (which your USB-C adaptor probably provides). Try using a cheap USB2 hub between the DigiSpark and the adaptor.

It's always a good idea to use a cheap USB hub between whatever experimental device you want to connect and your machine, so that if you wire something up incorrectly you don't end up frying an expensive laptop. This is particularly true for a device such as the digispark which does not have a real USB interface but really bit-bangs the protocol out of ordinary I/O pins.

There is no guarantee that the hub will protect you from all wiring mistakes, but it's an added level of protection.