If the issue is getting spun out on the downhill sections I think you will find that adjusting down the percent resistance slider smooths out things a bit. As a result you do less shifting and it is easier to grab some chain tension downhill. I would try this because I think it will accomplish what you are after.
Game vs simulation vs training: All I know for sure is that madness lies in the path of simulation. I’ve made careful efforts over the years using the software that comes with my CompuTrainer to match virtual terrain to real world speeds by adjusting my weight and drag coefficient. I’m still off by 5% and can’t get it much better.
I’m just one person and geeky enough to try and care. Throw in 50+ people who just want to ride and kill the mind-numbing trainer experience and abandon all hope of achieving simulation nirvana.
I think you can have great training while treating it as a game. Outdoor riding is a game, after all. I’m not riding the bike to pick up groceries 99% of the time.