Arcadyan KVD21 Gateway preventing my PS5 from connecting through ethernet

Recently just got a ethernet cord from a friend and expected better speeds than 7Mbps (which I have been having) so I can play Helldiviers 2 with my said friend and not lag or get kicked due to "connectivity issues" every 10 mins. Instead I got an issue with the ethernet, I connected an ethernet cord to my arcadyan KVD21 gateway then to my PS5 went to establish the connection on my PS5 it worked for 5-10 minutes, then it wouldn't connect with my PS5 saying that the router might be preventing the ethernet connection, and to make sure I can connect regularly (which I can) by testing the connection using my computer or mobile device. What should I do? Am I able to change from IPV6 to IPV4 so I can connect my PS5 through a LAN cable? Does the arcadyan KVD21 gateway not support ethernet connection to PS5? Am I gonna have to switch Internet Providers?