On amazon even normal switches have that term “splitter” in the description.
Even the TP-link switch that /u/1sh0t1b33r posted.
https://www.amazon.com/dp/B00A128S24
TP-Link TL-SG105, 5 Port Gigabit Unmanaged Ethernet Switch, Network Hub, Ethernet Splitter, Plug & Play, Fanless Metal Design
They include it because its a term many naive users search for.
That cable most likely does not meet specs for Ethernet.
That said, you could try to use it, and it might work (or it might not)
Use whichever pairs you like, but be sure you use the same set at each end of the connection, and that each pair corresponds with where an Ethernet pair should be.
This page has an image that shows which pairs go together:
https://doitforme.solutions/blog/ethernet-wiring-t568a-versus-t568b/
Either of those would work fine.
Keep in mine that your wired devices need to connect to to your router as well - the router isn’t just for wifi, in fact wifi is a *secondary* function of a router.
There are far too many variables to tell online.
Find someone that can come and take a look at your specific home and seek their advice.