On Omnibus F4 boards there are serial port/UART complications which can prevent GPS/telemetry/etc from working, particularly if you are using an SBUS receiver. And this is further complicated by the number of variations of F4 board that are available.
Not knowing what type of board you have, I would suggest you read all of the link below, and try the various work arounds. For my part I have an AKK F4 “V3” board and an SBUS receiver and was never able to get telemetry or GPS to work.
Same here, with an Omnibus nano v6. Flashed latest Plane dev 4.1, i can make everything (SBUS, telemetry, compass, etc) working BUT the GPS. Parameters are same of yours (apart speed, which i set to 38). I tried almost everything in params, neither. Before flashing Plane fw, i tried INAV firmware and GPS was working fine (so GPS is ok and wiring too). I’m quite hopeless … i don’t know what to try more.