From my experience, the proxy server port *can* affect performance if your ISP is actively throttling known ports. I’ve had better luck with 8443 (sometimes used for HTTPS proxies) since it blends in with regular web traffic.
For testing, DNSLeakTest is solid to check if your proxy is leaking. Also, avoid shared proxies—they’re usually slower and more likely to get blocked.
For testing, DNSLeakTest is solid to check if your proxy is leaking. Also, avoid shared proxies—they’re usually slower and more likely to get blocked.