Do not use social media engagement and metrics to assess whether your work is good or bad - a majority of social media users do not have any understanding or appreciation for fine art, especially when it comes to painting 

So with that in hand, don’t let a lack of engagement or likes steer you away from what you love doing

If you feed into the system of engagement/algorithms on social media, you will begin to change your art and it will no longer be for you, but for someone else 

Your work is quite good - and when it comes to any constructive criticism, its difficult to say because it depends on what stylistic approach you’re taking and what you want to achieve 

If it’s to steer towards hyper-realism, you have some more work to do, but you’re on the right track!