When I first started setting up Tutor I also had a similar issue with resources, if you have too many CPU cores then it will overload the RAM if you don’t have enough. I first tried with 8 cores and 8GB RAM but that was just getting eaten up very fast. Re-building images also had a tendency to fail. I ended up settling on 16GB RAM and 3 cores which has been rock solid since.
I haven’t actually tried this before, not sure if it’s even still a valid configuration - but maybe it helps, there’s a config you can specify the maximum workers. The default (source) is 4 * the number of cores for the LMS, and 2 * the number of cores for the CMS, meaning on a 20-core system you have 120 workers total