the OP asking to choose between 8 GB vs 16 GB, if there was an option to upgrade up to 64 GB then I would suggest going to 32 GB for future proof. Why would you have 128 GB of RAM and not know what your needs are ? going beyond 32GB right now is if your work deals with a lot of virtualization and running different OS for work, etc.
I saw a benchmark video testing the M1 with 8 GB RAM, the video showed the davinci resolve rendering and already took about 8 GB of RAM and the rest of it swapping to the SSD. From what I know, swapping memory to the ssd frequently is not a good thing.