Connecting Dynamic Track to a switch was probably not the cause of your problem. I have done it hundreds of times with no ill effect.
Most likely it was the siding and signal markers you mentioned ( interactives ) that hosed the route. The problem would be the same whether you placed dynamic track or a buffer of regular track next to a switch with interactive links. You should remove all interactivies
several sections away from the area where you a making modifications. Not that this makes you feel any better on losing all that
work, I mention only to point out interactives will quickly hose a route, sometimes by only clicking on a section that has an interactive placed or connected to it.
You are right, one can never be to rich, to thin, or have to many backups. Been there - Done that.