Since you are very young and are looking at long term survival as the goal, keep in mind that chemo comes with its own risks and long term side effects. For example the 'C' in MVAC, Cytoxan, has been shown to cause bladder cancer. This drug is used in breast cancer as well (my sister had it) and is given with a bladder-protectant drug Mesna. If a person survives long enough there's a big risk of bladder cancer down the road. If one is post-op and bladder-less I suppose it's not as risky (maybe).
That brings us to 'risk vs. benefit' and that's probably why chemo isn't given in your situation of early stage TCC, the numbers don't warrant it. There's also the Oath to "First do no harm". The newer drug combos for advanced bladder cancer are so new there are no long term data to call upon, so we can't be sure that it's a good thing for a person in your situation.
It's very hard for uro-oncs to know when exactly they are over-treating or under-treating. Nobody would want to give a man your age toxic drugs that might not even work...unless spread was near-definite and response could be tracked.
Early stage bladder cancer treatments, immunotherapy -which you are doing- is all about stimulating the immune system. Chemo does the opposite and might even be bad for your condition. It's not for nothing that it's reserved for high risk cases where spread is confirmed or at least highly suspected.
Wishing you all the best,
Wendy