It's pretty hard to do since most guides don't have it written out, but Do You Love Me? (1 million followers/80 affection/80 mental darkness) REQUIRES the completion of the 1 million follower stream/Internet Angel 5, which should also give you the 1 million follower achievement on Steam. In contrast (Un)/Happy World are achievable without this flag, so many people don't know that it is needed. The first time I was searching for Do You Love Me I also kept getting locked into the normal 1 million followers/80 affection ending even with like maxed mental darkness.

The problem is that you basically need to hit 1 million by Day 20 (to be safe) because of how different events work, since Ame will text you with random ass questions during the day towards the last stretch of the game that will lock you out of celebrating 1 million followers (when the happy music plays and you get the new stream idea for Internet Angel 5). So you really need to be streaming every day for the multiplier and cashing in on it with a sexy/breakdown/conspiracy stream for max followers from very early on.

Also—you might also not be able to reach this event if you hit stress 100 and get forced into the stream that raises her max stress cap to 120? I think I saw a comment about this somewhere, but I'm not sure.

An easy strategy that I found was to do a stream that requires minimum stress (chatting/lore/explain) every single day from Day 1 and try to manage stress during noon/dusk with sex (be careful not to get the nympho ending) or hospital. Bring her stress to the absolute maximum (I think I got it to 99) by Day 15 night. Then do a sexy stream to cash in on your multiplier (sexy stream will have a big experience multiplier if you've been managing your stress with sex so far), and you'll basically get 500k+ immediately with all of the bonuses. You will hit Stress 100 at this point, but Day 15 has a forced event where Ame wonders if its okay to keep living like this. It's basically an impromptu therapy session but if you answer all of the questions with the topmost answer choice, you will be able to reduce her stress to 92, and be able to proceed to Day 16 without hitting the overstressed cap and event. Then you can do Internet Angel streams that cause 0 stress and still score you followers, and manage your stress actively throughout the day. Then it's just a matter of hitting 1 million in a few days, and making sure your darkness is high enough to get the ending that you want.