There's a step between the reel and the follow that this thread keeps skipping, and it's the one number that would answer your question. A view is delivery, a like is a reaction, but a follow can only happen after someone leaves the reel and opens the profile. That step is reported per post as profile visits, so you don't have to guess at what changed.
Pull that column for a recent reel and for one of the older reels you're comparing it to. If reach went up and profile visits stayed flat, the post isn't sending anyone to the profile and the fix is in the post, usually because the reel is complete on its own and gives no reason to look further. If profile visits went up and follows didn't, people did arrive and then declined, and the fix is the first screen of the profile rather than the content.
One caution on the comparison itself. Similar reach across two different months isn't the same audience, so the ratio to trust is per post, not month against month. Two posts, two numbers, and you'll know which half of the funnel to work on instead of arguing about the algorithm.
Best,
Floqal
