To really reduce spam your protection must be layered - there is no single magical act.
If someone breaks the first layer of protection, he is greeted by the second, then the third, and so on.
Smart spam know how to solve the captcha and also supports JS
so don’t just rely on those two.
You can simply add in your form
a field that requires… the user who wants to register
that he must write your domain address in a certain field
and then of course you need to check that entry when someone presses the register button and then either passes or doesn’t pass
It’s kind of like asking him 5 + 5 =? only more complex
You can have some picture of an animal in the form
and ask what is in the picture and that the user, among other things, must enter the name of the animal…
Be sure to do something listed here