If the scope or mirror is below the dew point, condensation will form on it, so you either have to warm the scope and mirror or decrease the dew point of the surrounding air. Don’t think there are any other options.
I can think of another, one employed by myself, Kevin Hills and numerous others.
Move your scope to a site where dew never happens. Operate it over the interweb thingy if you don’t fancy moving yourself as well.
Admittedly, not very appealing to some folk.
😎