Not quite sure what your specific question or questions are but the UA Mountain Running plans might be of interest to you: https://uphillathlete.com/training-plans/#mountain-running-training.
In response to “I am talking about certain rules, like incorporating rest days every xyz days or intensity sessions once a week”
– I believe consensus is 1-2 intensity sessions per week (perhaps less during certain periods). I think this is discussed on the Science of Ultra podcast Coaches Corner Number 5, Speed Training For Ultras
– rest days: probably depends how you define a rest day, but assuming that means only recovery work, I would guess 1-2 per week would be a standard recommendation, with build/recovery cycles of ‘2w on, 1w off’ or ‘3w on, 1w off’