There is no universal law. Each patient is unique as is each malignancy. However, in large patient populations there are different pathways:
1: Low grade. Can require continuous treatment (TURBTs + BCG or localized chemo/ICI for many years).
2: High grade PT0/1 (with CIS): BCG can be attempted but risk for body-wide spread is always there (although low).
3: High grade PT2/3 (with CIS): BCG is not an option nor is localized chemo/ICI. Heavy systemic chemo (CG or DDMVAC) (+ pembro, rarely) and/or EVP. RC is the curative intent therapy in most cases. EVP is gaining popularity and for select patients TURBTs+chemo+radiation. Sadly, many patients turn out PT3 or N+ after RC. Neoadjuvant chemo as mentioned is common but fails 30-40% of patients making things worse.

Irregardless, DNA profiling (TP53, SOX4 and such) can help assess risk factor and urgency of treatment.