Stay put. I went from regional to ACMI to legacy. Starting out on year 1 pay twice is financially devastating. Most ACMI outfits are on the whole no better than regionals as far as pay/QOL issues are concerned. Since you drive to work the home-basing they offer isn't a selling point (not if the price you pay is ultra-long trips, as is usually the case.) I'm fairly certain heavy international time is not as impressive as more TPIC or check airman time.
You'll have plenty of time to fly heavies around the word when you get that legacy job.
Volunteer. Get a checkairman/management job.
Focus on that.