Liking post in your niche 2019

What are you getting from liking post in your niche?
Most people on bots are doing this from a long time so I made some tests and I found no benefits.
I made a set of accounts posting with hashtags, no likes and no follows, second set the same plus following a few accounts in the niche with millions of followers. third is as second plus regular follow/unfollow plus linking the posts of my followers, forth as second, plus regular follow/unfollow and a lot of likes to posts in my niche.
The likes received from accounts that I do not follow were better with the second set and the largest amount of total likes came from the third set. The poorest results came from the forth set making 250 likes per day.
For me the forth set is a waste of time, considering most people booting do this and there is the chance that IG knows. Instead, liking the people following me increased my engagement in a 30%.

Please let me know your experience or if there is a good reason at the time for liking posts in your niche.

Thank you

Liking your own followers will increase it for sure since some might not even remember your account or seen your post in a while.

Keep an eye on the amount of likes those post you are liking already have, your like will be more noticeable in a post with 10 likes (for example) than in one that has 800.