Engagement Issue

I have recently taken over an instagram with 3000 followers that hadn't posted in 2 years in the fashion niche.

The account was getting 200-250 likes at one point but since posting i get no reach and about 5-15 likes on photos I'm posting. Any idea why this is happening and any way to fix it?

On my other account as well I posted a video at the start of last week that got normal engagement (180 - 200 likes) and posted another video yesterday which only got 70? Not to mention previous photos videos were getting about 300 +..

Any help would be appreciated

Things should get back to normal.
Just keep posting regularly and multiple times a day 2-3 posts per day should be enough.
Take a look at similar accounts (approx. same amount of followers as yours) in your niche and see what type of content and hashtags they are using.
Don't copy exactly what they do but mix it up.

i dont have enough content for 3 a day. I can probably do 1 a day at the moment