The best (possibly paid) open PROXY server list service, which one to choose?

Question

Computer networks

We need a service that, upon request to the API, would provide a random anonymous https proxy server. It is possible that there are not many of them (from 20 to 100 will do), but that the connection with each would be guaranteed to be checked.
Found gimmeproxy.com
There is an API, but every time it returns non-working proxies, or they have self-signed https certificates and, accordingly, it is not possible to connect to https://internet.yandex.ru through them (to check their own external ip).
I also consider paid services, but it is necessary that the proxies are guaranteed to be available with normal certificates.

Answer 1

I have a http proxy checker product. He can be fed a list of procs. and he will check them, very quickly.
You can organize 10,000 threads at once.
It needs development, so I can sharpen it for you for a fee.

Answer 2

There is a proxy checker in python, if you are interested, in HP.