How to scan when we have multiple lcov.info files in a UI project

How did you get 70%? Can you explain how you got that value?

Let’s try this: find an example of where coverage is incorrect in one of your source code files. You can use the SonarCloud UI to easily find where coverage doesn’t match your expectations or check the HTML report output of your coverage tool and visually check there.

Also consider the point made here: C#/VB.NET: SonarQube and SonarCloud support Branch/Condition Coverage data

Since SonarQube 8.3, the code coverage for .NET projects now takes into account the branch/condition coverage in addition to the line coverage. The coverage of your projects may decrease to be closer to reality, and it can impact your Quality Gate.

Alternatively, if you can share your entire project and pipeline with me (you can share privately if you want) so I can reproduce the issue or if you can share the HTML reports with the LCOV reports, that will be helpful.