Orient, that's interesting to have so many races as well as age graded overall rankings. Here in the States for both running and XC skiing we have an overall association (USATF and USSA) and regional associations. Just four or five regional associations for skiing, dozens for running.
Masters skiing is much more diffuse, but they do have regional championships and usually designate a national championship weekend, usually involved with an associated loppet (marathon for non-skiers here), with a shorter race (e.g., 10 or 15K) , sometimes a relay, and then the loppet. The results are stand-alone. There isn't much for rankings at the masters level, although that becomes more important for juniors, and vitally important at the senior-open level (age 20-34). There it's all about FIS or USSA points.
For running each association will have a few to several races a year. In Colorado we have had 3-5 races most years, and this year for the first time that I can recall they had a points system, but just based on age group. We had something like 7 races and you had to compete in 4 to be eligible for (some actual money in 2021) prizes. I missed out on that because only entered 3 events. But it was all by age group (Open, masters by 5 years I think). No age grading at our association races (at least ours). Each association is going to be different and generally you are not eligible for prizes (even a medal) for races outside of your association.
At the national level there is a 5 to 10 race Grand Prix for masters each year, and a separate one for open (pro/semi-pro) runners. The masters grand prix includes races all over the USA, but mostly on east or west coast. You get age group and team points, and they require completion of 4 races, with up to 5 counting. The age grading is only race by race (i.e., they'll have an age grade ranking for each race but not cumulative points or averages for that). It's a pretty big commitment to travel to more than a couple races a year although some teams have a travel budget.