That's the reason, I avoid going to relatives home as guests. They would compel and force me to eat something that I don't prefer. I won't be able to politely decline them as I'm from guess culture.

Why wouldn't you be able to decline them? I have relatives like that too whose insistence is seen as politeness but even they will back off after some time, especially if (but it's not needed for you to) explain why you decline.

There's both local and cloud version of the app. The cloud version of the app runs from the infra that he manages. Hence, he would liable for the violations that happen using the cloud platform that he manages.

Would using a separate service email accounts help mitigate issues? [email protected], then [email protected], [email protected], etc? That way my primary email would stay private and will used only for email, not for identity.

Your private email that you don't use for signing up anywhere is irrelevant except for phishing and spam. Your secondary email address will become the foreign key that is used to correlate the datasets from everywhere you signed up with it. The +tags can just be removed since it is known how they work. Might give you a small protection against attackers who don't know about email address tags.