my experience is anecdotal at best, but so far realm works has been surprisingly stable even with throwing several very large maps cluttered with objects at it.
the main reason for the large map export is the way CC3 handles text objects and object scaling combined with sheet effects. also helps if you're doing sub regions rather than a zoomable overworld view in region detail
Overall RW is everything I hoped for, and the stability in handling large files just backs that up!