Hi, Here's the suggestion https://www.tp-link.com/au/faq-2236.html Contact tplink support if problem not solved.

Hi, C5 has USB 2.0 port. That speed is normal.

Hi, Cannot disable physical reset button. Not on other tplink routers either.

Hi, Do you experience any security issue? There aren't any feedback like that regarding the router. Usually update will be released if there is any issue.

Cable modem router like TC-W7960 cannot handle it. It's available on some wireless routers, like this one C50 V2

Hi, Can you access the server from LAN? Have you opened port for the sever? https://www.tp-link.com/en/faq-1797.html Make sure the internet IP address of Deco is not private, otherwise you need to...