I think you don't need to know much about it, you just need to choose a good dependable proxy service provider that provides secure proxies appropriate for your purposes and purchase proxies only from them. I, for example, buying proxies only from Rayobyte provider, it provides its users with very good reliable trusted anonymous proxies https://gologin.com/best-proxy-server-services/rayobyte
I would like to find reliable proxy servers for work. Who uses proxy servers, please tell me how to choose good proxy servers? Because I don't know much about it.