Constantine's fight against Maxentius was not fought as a Christian vs a Pagan. In fact Constantine was not a Christian at that time and he was fighting for non theocratic reasons.
I dare you to name one Christian armed revolt against the Roman authorities.
" dare you to name one Christian armed revolt against the Roman authorities."
Don't be making strawmen up. Who said anything about armed revolt against Roman authorities?
The Christian minority got into positions of authority in the Roman Empire and used the power of authority to force Christianity at the tip of a spear and the power of the state (such as by giving Christian priests tax-free status, just for example).
BUT one example of Christian armed revolt against the Roman authorities involved Julian. Julian moved to abolish privileges that had been bestowed upon the Christian clergy. This resulting (in part) in Shapur's uprising. So, in 363 (? 360ish), Julian had to lead a military campaign against Shapur II, pushing Shapur's forces back to his capital, Ctesiphon. (Interestingly Julian's died shortly thereafter of wounds suffered in the continued campaign against the Persians.)