Hi Aleksandra,
Thanks for reaching out to the Google Ads API team. I hope you are doing well today.
Please see my response to your questions below.
1.) I have a question why the match rates for our CRM audiences have increased with the new Google Ads API?
Regarding this, can I ask how you can say that CRM audiences have increased since you used the new Google Ads API and could you please provide a full screenshot of the Google Ads UI that shows your CRM audiences have increased in the new Google Ads API so that our team can better investigate this concern?
2.) What is taken into account with audience lists and match rates?
With these questions, you may refer to this documentation Customer Match as it contains the customer match considerations which will be your guide on what are the key points you keep in your mind.