[CA] SonarChart vs. SonarChart Live

Hi,

I have just bought an Axiom 7DV and want to better understand how the downloaded SonarCharts from Navionics and my own logged data (SonarChart Live?) are handled and how they can be separated. I don't feel I can trust all data after reviewing them on some for me known places. It just looks like interpolated depths from the base chart and not based on measurements on many places.

I want to be able to at some places look at all SonarChart including my own loggings and on other places/occasions only look at my own logged depths. Is that possible?

In other words: If I download the SonarCharts from Navionics, is it be possible to just use my own logged depths as SonarCharts?

If I downloaded the SonarCharts onto my included Navionics+ card, is it possible to remove the downloaded SonarCharts completely from the card in order to just have my own logged depths together with the base charts displayed.
If so: Will I lose my already logged depths when I remove the downloaded SonarCharts?

Many related questions, but I hope you understand what I want to know before I download any SonarChart.

Regards,
Ken