Viral reels growth kills engagement?

Just something I thought was interesting and curious of others opinions. So a lot of us are trying to grow accounts per reels myself included but here's is something i noticed with my friends account.

he runs a fanpage for a celebrity he uses to sell stuff to younger audiences he has had this account last couple years and its been sitting at around 25k followers for a while his engagement rate was 10-12%. couple weeks ago he post two videos reels of this celebrity on the account and they went viral after a couple weeks one is sitting at over 10 million views and 1 is sitting at over 3 million views. he is now sitting at 95k followers gaining 70k in just a couple weeks. All sounds good right? but kicker is now whenever he posts he is lucky if he gets a 1% engagement usually more like .5%.

has anyone else experienced this with reels growth?

I have experienced this, before reels were a thing. The higher up in following you have, the engagement will be worse

That is how it is when you get more followers. Now most of the followers that came through one reel followed you because they liked the reel, but they may not like the content you continue to post, thereby not engaging with that content. When the account grows the engagement rate reduces. It usually settles at around 1-3% in most cases when it comes to theme or fan pages.