I have a Ethernet only Epson WP4515 that I plan to keep until it dies since it works perfectly with 3rd party cartridges. In order to add WiFi, years ago I took a TP-Link TL-MR3020 mini router I got for €5 at a flea market, put OpenWRT into it and set it up as a wireless bridge. Worked perfectly for years until I could finally put the printer in a place to connect it through Ethernet. Any piece of hardware with the necessary features (compatible with OpenWRT or any other Linux, Ethernet, WiFi) can be used, therefore many *Pi-like boards will also work, but repurposing an old router/AP will be the cheapest solution since they're often literally thrown away.