My Medium Blogs Dropped from SERP - But why?

Hey folks!

Hope you all are good!

I have written around 5 blogs on Mediums so far and I have recently noticed that two of my blogs appeared on Google but only for a limited time. I am not sure what could be the reason behind it.

I understand it is hard to identify the exact reason but could you please tell me what improvements shall I make to expect those pieces on SERP again.

Also, I did on-page SEO but didn't work for linkbuilding much. But if linkbuilding was the reason, the blogs might not have appeared on SERP in the first place.

Any help will be appreciated! Thanks!