Hi

This is a serious issue, my only advise would be to see what tungsten
bits could replace the chainsaw chain, ---- Still even such for routers
are soon vorn out but it is the way profesionals work ,cutting
fiberglass it also make a much smoother cut with a router and tungsten
bits --- they work longer and can be sharpen but you need to send them
to a workshop, as this ask special mashines not just the sharpening
stone.
-------- But maby a router bit don't reach enough.