I am looking for an alternative for recaptcha, ALTCHA looks interesting has anyone tried it ?
Nope, since we moved to Turnstile we’ve never had any problem.
I was interested in Altcha before and your post reminded me of it.
I had some issues with some users when using turnstile, so I built this little package:
It integrates the basic Proof-of-Work Validation that Altcha does. I have tested with v.9.4.1
I am happy for feedback 
Thanks for this I will check it out and let you know