In the Office, I reached level 8000. In the event, i was stuck at ~1640 playing almost all days from the beginning of the event.
Luckely, I got the idle to click artefact for 2M, then the event became really easy, and I will finish the event in few minutes (I just wait the power cooldowm to use them all on the last girl).
I think I would have been able to finish this event without idle to click artefact, if I got other usefull artefact(s) for 2M or/and 4M (at this state, I think only 5 useless artefacts were remaining). But if I was unlucky, the event would have been impossible to finish (without buying boosters).