What was the engagement prior to your absence?
You have very low engagement, my Girlfriends account has 500 followers and gets 200 likes organically.
I took 6 months off posting on my 8k and 165k pages and didn’t see that much of a drop,
Have you added fake followers or smm bot?
Do you post original content or repost?
How many story views do you get?
A way to boost it temporarliy is to go back to when you had more engagement and write down all the users that were constantly liking your posts. You can scrape post likers with jarvee and use excel to find duplicates.
Like and comment on these users posts. You can even dm them saying you have been sick and not active. But are back in action.
However, if your page has always been screwed then you will need to get rid of inactive users and fake followers. This ruins your engagment. Then start working on making better content and getting people engaged.