Cloudflare's CAPTCHA is Turnstile. I've found it very useful. It doesn't use pick the image or type the text, it's just tick the box. You can even set it to invisible, then the user doesn't need to even do that, the challenge is sent to the browser and is completed automatically.
https://developers.cloudflare.com/turnstile/
In terms of privacy, it's is still Cloudflare, but at least it's not intrusive to the user experience.
Cloudflare's Turnstile has an invisible mode that you're probably using in a lot of places and aren't aware of it. It provides an invisible challenge to the browser and requires no interaction. I would say no input require in quite user-friendly.
Yes, both SL and addy.io have the feature to enable/disable individual addresses.
They both will automatically create an address on-the-fly. Give a service [email protected] and it will automatically be generated and sent to your mailbox of choice.
First purchase a domain. Cloudflare is definitely the cheapest but there are other options out there if you don't want to use Cloudflare.
Use an alias service like SimpleLogin or addy.io. addy.io has a cheaper 'lite' (limited) plan, SL has a cheaper 'premium' (unlimited) plan.
I highly recommend crDroid. It's super customizable and has a good battery life / performance ratio.
You have to add the FUTO repo https://app.futo.org/fdroid/repo/