You don't need gigabit even for 4k hdr. Their maximum nitrate is 70mbps.
Connect a rj45 usb convertor to xiaomi
Minix T5. It's Google certified and has a gigabit ethernet port. As an FYI, even though it does have the correct Widevine DRM for Netflix, it still isn't Netflix approved.
Walmart-only Jetstream 4K?
In Australia only. I have one, also has tuner. Totally certified, but no official Prime. Sideloaded Prime just fine and does HD Prime. https://www.vodafone.com.au/vodafone-tv
Usb to ehernet would be a good solution
Most with 100Mbit only devices simply buy a Ugreen USB3 > Gigabit LAN Hub adapter.
Minix Neo T5
Go with a Shield.
Gigabit is really not needed for streaming.