In Lives of the Saints (Butler's?) it is mentioned that Constantine was a heretic. But wasn't Constanine a Pagan who later converted to Catholicism on this deathbed, baptized by a semi-Arian?
The Arian situation was a difficult one. St. Servatus stood firm in the faith, and tried to denounce the heresy of Arianism. But did the actual Church ever declare that those who unfortunately followed the Arian heretics were not to be considered Christians? We don't really know much about what followed in the aftermath of the start of the downfall of Arianism, after it was condemned by the council at Nicaea in 325.
In any case, St. Servatus was a teaching bishop. We are laity. Unless you consider that we are on the same level as Catholic bishops. That's something that the new synodal church teaches, as supported by Pope Francis, wouldn't that be correct?