your problem is not keeping up with your ranks, you need to start spending all your energy/prestige on rank exp, that will make levelling up a lot easier.....also you get new synergies at 100, 150, like you saw. You also get new combat styles which make a massive difference. Another problem, is you are not maximizing when you spawn the trainer....you need to switch to desert map and have a much more efficient setup....lot of these things can be talked about within the games active discord.
you need to upgrade your damage hero's. using a Ele at wave 4k is where all your power is held up. you should have used warlord after 2k with old patch.
