I tried following various guides and tried out all different tactics, but still, they didn't work for me. And this achievement was the last I got! But now that I did, I can share some stuff that helped me :)

• Watching Ame's streams and deleting mean comments slightly curbs stress received from the stream.
  
• Smoking weed significantly reduces stress, I did it a lot after I ran out of stuff to do during the day.
  
• If you have only one short task to do during the day, you can sleep as another task. It only minimally reduces stress and dark thoughts, but it's better than nothing.
  
• DON'T SKIP STREAMING NIGHTS!!! You get a streaming bonus for staying consistent, and it's crucial here.
  
• Focus on highly rated streams. Worth of all different streams is listed on NSO's wiki. I used less useful streams as fillers, and when Ame's stress levels were too high for more tasking ones.
  
• Keep Ame's stress level under 100, otherwise you can get other endings.
  
• DO NOT get th level of sexy stream and conspiracy theories, as they trigger other endings.
  
• On the same note, don't do breakdown stream lvl 3 until day 29, as it forces Ame to take a break from streaming, which you can't afford.
  
• Hospital dates are useful for reducing dark thoughts, while still reducing stress and adding affection.
  
• You can keep Ame's dark thoughts at 100 safely after day 20 I think.
  
• (I'm not sure if it's because of taking magic paper twice or getting Rabbit Hole bonus x33 after conspiracy theories lvl 4, or maybe something else entirely BUT) after one of those things, Ame doesn't get stress after streams. I took advantage of that, and did all four levels of sexy streams.

1. On the first day, do one short action (I made a tweeter post), then as a second action choose SLEEP UNTIL TOMORROW. Thanks to that, you unlock this stream without skipping a streaming night later on and breaking the streak.
   
2. Do first 4 levels of CONSPIRACY THEORIES stream, to get x33 Rabbit Hole bonus and (possibly, maybe) be immune to streaming stress later. It's also worth a lot!
   
3. SAVE BREAKDOWN STREAM LVL 3 FOR 29TH STREAMING NIGHT. It will give you enough followers to hit 9999999, and by then you don't have to worry about breaking the streak anymore.

Thank you for clicking on my guide! I hope I could help in any way.

I wish you all the best, and good luck with getting your achievement!

I'd greatly appreciate feedback :) Feel free to add any other tips in the comments for others.

And if you got your achievement already and read it out of curiosity, or you came back here, congrats!!!