You can learn a lot from /r/degoogle, or r/privacy.
If you are interested in this kind of best practices, here is a book I recommend
https://www.amazon.com/Art-Invisibility-Worlds-Teaches-Brother/dp/0316380520/ref=sr_1_3?dchild=1&keywords=privacy+big+data&qid=1607193854&sr=8-3
You can start signing up with mail like Protonmail, use different email address for every category (Protonmail gives you alias email address, manage different users, etc from 1 single account):
- social media
- work/friends/family
- troll account
- gaming
- crypto
- online marketplace
- etc
- but most of all, never give your primary email address, to anyone.
The Art of Invisibility: The World's Most Famous Hacker Teaches You How to Be Safe in the Age of Big Brother and Big Data https://smile.amazon.com/dp/0316380520/ref=cm_sw_r_apan_glt_i_587NB08C8Y8BPD80P8K5
Good luck!
I can recommend a few books Kevin Mitnick's The Art of Invisibility
How To Have Impossible Conversations: A Practical Guide
Crisis Management: Mastering the Skills to Prevent Disasters
Personally my experience is that I usually came out first or was just out and didn't care who knew. But I was kind of outed to my depressingly social conservative mother by an ex-boyfriend and at that point I realized the only thing to do was just roll with it.
So, yeah, if somebody is maliciously outing you the only thing to do is accept that it is happening and take control of the situation. Read up on communication strategies and take control of the narrative. First, make sure you have plans if your financial or housing situation might become unstable. Then just bite the bullet and talk to your parents about it.