That may “work” if you don’t mind the ancient slow speeds it will provide or your connected equipment hogging the connection dropping your music.
Considering a Gigabyte Ethernet Switch is around $20 it seems hardly worth trying.
8 port is cheaper than the 5 port.
https://www.amazon.com/gp/product/B00A121WN6/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1
Hi @msskov
Welcome to the Sonos Community!
Just to expand on @Stanley_4’s sound advice, what you describe used to work, as long as the device with the ethernet ports was connecting wirelessly to SonosNet (not WiFi). Whether it would still work these days, I’m not so sure, but I think so.
It does make far more sense to use a switch, as suggested - Sonos ethernet ports are 100Mb maximum, and Sonos systems generally do not take kindly to other devices using up their bandwidth (audio doesn’t take much bandwidth, but other uses can).
I hope this helps.