Post not displayed on search

Recently I published 3 posts on dev.to. While searching on some keywords present in the title, none of the my posts are listed. For E.g below are three posts titles

• COVID-19 EDA and Prediction using .Net Dataframe and ML.Net (C#) - Introduction
• COVID-19 EDA and Prediction using .Net Dataframe and ML.Net (C#) - Exploratory Data Analysis
• COVID-19 EDA and Prediction using .Net Dataframe and ML.Net (C#) - Prediction

Now on searching with keyword such as 'COVID-19', none of the above are listed.

Is there anything I missed as its my first post. Not sure it has reached to broader audience.

Anything I could do improve the search results.