The issue you're experiencing seems related to how your network equipment handles and prioritizes traffic when streaming high-bandwidth content like Netflix through multiple devices or connections.

Here are some points worth considering:

1. The speed variations could be due to the way different devices handle Ethernet negotiation, particularly with gigabit (1000BASE-T) vs standard 10/100 BASE-T speeds. Some switches may not always negotiate properly when there's a mix of device types on the same port or cable.

2. When you connect your laptop directly to the router without going through the switch, it bypasses any potential negotiation issues between devices and/or ports that might be happening with multiple devices connected (even if they're not actively using them at the moment). This can sometimes result in a more consistent and higher reported speed for applications like Netflix.

3. The fact that you consistently get around 89-90 Mbps when directly cabled to the router suggests your internet connection is fine, as well as your TV's Ethernet port and cable (since these are not affected by the switch). This also rules out issues with either your ISP or the DOCSIS modem.

4. Since many other tests show that both the switch and cables seem fine when used independently, it may indicate a Netflix/TV specific issue rather than a general networking problem.

5. One potential cause could be how Netflix handles Quality of Service (QoS) for its traffic over different network paths or devices. If your TV's Netflix app is not correctly configured to prioritize QoS on the switch port that leads directly from it, this might result in lower video quality when watching through other connected devices.

6. It would also worth checking if there are any specific settings within your router (or switch) that can force traffic over particular paths or prioritise certain types of data packets (such as those used for Netflix streaming). Sometimes these features need to be enabled manually on the equipment itself rather than just being set up through software.

7. Lastly, consider updating all relevant firmware and drivers across both your network devices and client machines to ensure you have the latest security patches and feature updates which may address any known issues with specific configurations or manufacturer combinations.

If none of these suggestions help resolve the issue, it might be worth reaching out directly to either Netflix's customer support (as this could potentially be a platform-specific problem) or contacting your router/switch manufacturers' technical teams for further assistance.

Netflix app for testing internet speed