There are more sustained damage sources available that radically reduce the time it takes.
Hey guys, Just a heads up, Endless will be balanced for solo play in the next patch, which should make this easier to achieve without a party.
@CremoAcanthis hope to see the ironside video soon and ill be forever grateful.P.S. I actually got these 2 achievements before seeing your video and my alternative ( a bit easier in my opinion) is to use "the wall" map (use the lowest difficulty, not endless) and as much as possible delay the breaking of the gate with stuns ( decoys could help and remember to stay in front/outside of the gate taking in aggro but not killing any minions) and this could be done on the FIRST WAVE SOLO . the minions will flood ( hehe floodgate) and boom achievement achieved.
i did several times 34-39 waves in 1,5h or so. 0 damage to barricade, 0 damage to guardians, 100% damage to hogarth. full time in the frontline under tnt/lava elementals/grenadier attacks including the time between waves and the tab screen at the end (because of traps limit cant go far) said "minions damage 2,5kk and another run was 4kk", but the endgame page always shows 20-30x lower result. something isn't right.