Quotas and price charge for services running in a App Script Add-On as user in Google Workspace

Question

I'm developing an application to run as Add-On in the Google Workspace Marketplace and after reading all the questions already answered here still not clear the quota limit and cost for an App Script that runs as Add-On and call for APIs other them those like mail/drive/sheets from the App Script env.

My question is:

If an application running as Add-On in the Google Workspace Marketplace that consumes :

a - Google Cloud Search API
b - Gemini API
c - Gmail
d - Google Sheets
e - Google Maps

And is installed by an external user (not from my company).

1. The quota (number of requests) is per user or falls under my developer account?

2. If the user doesn't have services like (Gemini API) activated, is possible for a thirty part user activate it and consume for that particular user in their consumption?