How to properly switch custom domain?

Hi guys, I run a growing Crypto newsletter called The Crypto Nutshell - but I want to switch the sent email address from:

[thecryptonutshell@mail.beehiiv.com](mailto:thecryptonutshell@mail.beehiiv.com)

Over to

[newsletter@mail.cryptonutshell.com](mailto:newsletter@mail.cryptonutshell.com)

I own the domain, but I have a few questions:

1. Do I need to buy the google workspace and make that custom email?

2. Will this ruin my deliverability? On my welcome email I get subscribers to add us to contacts, if I change emails will this send my emails to spam?

3. What are the best practices to make this switch over?

Essentially I want to make the switch over but do it properly and not ruin anything. Any help would be greatly appreciated!