In my experience with over 40,000km on Shimano hydraulics, the only servicing is swapping pads when the pad wear spring starts screeching against the rotor.
My early 2000 era Magura hyrdros were a bit shit and required a lot of maintenance and issues with sticking callipers, but shimanos made in the last 15 years are pretty much perfected and maintenance free.
In my experience with over 40,000km on Shimano hydraulics, the only servicing is swapping pads when the pad wear spring starts screeching against the rotor.
My early 2000 era Magura hyrdros were a bit shit and required a lot of maintenance and issues with sticking callipers, but shimanos made in the last 15 years are pretty much perfected and maintenance free.