Drivers for your ET4550 under macOS Sequoia are available here:
https://epson.com/Support/Printers/All-In-Ones/ET-Series/Epson-ET-4550/s/SPT_C11CE71201?review-filter=macOS+15.x
If you get to the Epson page and the drivers are not visible, click the Downloads button. Then you "may" need to refresh the page multiple times to get the OS selection to show up. That page has been weird for some months now and the workaround appears to be multiple refreshes until the OS selection shows up. Even after selecting the OS you may need to refresh multiple times. Sorry, I'm just reporting how it has been working lately.
There *are* drivers for macOS 15 ... printer driver v 13. 26 dated 10/22/24 ... CISS_1326_NA.dmg. There is also an ICA scanner driver (which you will need if you use Image Capture and some third-party scanning apps)