What ROA have you used? I once took a dose (snorted) that was 80-100 mg (the stuff was degraded and I thought it was almost useless, leading me to take an insane amount. Extremely stupid of me) and it caused a blackout that lasted for about an hour. When I returned from the blackout (which I obviously have no memories from) it took hours to understand even basic things, like words, who I am, what the computer in front of me is, what planet we're living on etc. Basically my whole perception of reality was smashed to pieces. It was more intense than any experience I've ever had with DMT or 5-MeO-DMT.
There's quite a big difference between taking 4-AcO-DMT orally or snort it. I almost always snort it (I have a snorting fetish), and ego death appears with 25mg+ doses. Are you sure the 4-AcO-DMT you've had when taking doses up to 70 mg was pure? It just sounds incredible that such an insane dose wouldn't produce effects like ego-death.
I agree that ego-death is achieved more easily with 4-HO-MiPT, and with much smaller doses than with 4-AcO-DMT. 4-HO-MiPT is considerably more potent than 4-AcO-DMT. 20 mg 4-HO-MiPT insufflated produces ego death, fusion of the senses (music is clearly visible as a fractal chain), and insanely strong visuals (it's a more visual compound than 4-AcO-DMT, but not nearly as deep).