Workers are great for this sort of thing and these days with Turnstile and Email Sending beta[1] you can have Cloudflare handle it all

1 - https://developers.cloudflare.com/email-service/

That was my thought too .. why use anything but CloudFlare for this? Turnstile works great and it can send email itself.. why go external?

Cloudflare Workers and HTMX also pair up well.