@Roller
Hi, for the issue, I would like to confirm the below information.
When you unplug the switch to the virgin router, can the router provide stable connection for your clients?
Can you connect the PC to the same port of the router with the same cable to check the connection?
When the internet drops out, can you check if the lights' status on the virgin router are abnormal?
Both WI-FI and wired connection from the router dropped out in your house?
How to recover the internet? Does it work when you restart the router?
Have you tried to contact the support of virgin router to check?
After you connect like: Router----cable-----Switch-----cable----PC, can you follow the instruction to check the IP address, default gateway on the PC?
https://www.tp-link.com/support/faq/838/
Look forward to your reply.
Good day!