Welcome to the community and thanks for posting.
Sorry to read that the wireless connection doesn't work when the Ethernet ports are in use. This is unusual.
Do the devices still show as connected to the network when this happens?
Does this happen on both 2.4 GHz and 5 GHz?
Have you tried a factory reset (be mindful that any saved settings will revert to default settings) to see if that helps?
Does it only happen when all 4 ports are in use? Just wondering as if you had 3 in use, then connected a fourth does it then stop working as it might be the cable?
Let us know how you get on
New around here? To find out more about the Community check out our Getting Started guide