#1
Hello dudes!
I've been using so far 0.9-42 rotosound regular nickel on steel strings and I've got a simple question: If I switch to thicker strings(10-46) or 11-48, will they wear my frets more than the thinner strings do?
#2
No. Fret wear is largely a result of what the strings are made of. Stainless steel strings are made of a harder alloy than are nickel steel strings, so they wear the frets faster.

A larger gauge of nickel steel strings will not wear your frets any faster, and even switching to stainless steel strings isn't going to wear your frets out anytime soon. It would make a difference only if you could somehow use freakishly large strings. Bass players sometimes complain about stainless steel strings eating their frets faster, but bass strings are huge and the spaces between the outer windings can have something of a a file-like effect. Even so, people play roundwounds on their basses every day for many, many years before they need a re-fret job.