Purchase the domain with cloudflare, for email it depends how you use it:
With an email client like thunderbird:
A cheap service like mxroute is perfect
If you need to use a webmail:
You need to pay a lot because the free webmails are all unusable for advanced use.
Good options:
Zoho at $1 per user per month
Exchange with ovh at €3 per user per month
Bad options:
Google workspace at $10 per month per user plus the blood rights for your firstborn and pray that they don’t alter the deal
proton pro at $9 per user per month but IMHO is extremely overrated for what they offer at their price point (unless you need end to end encryption when emailing other proton users)