What this OptiMOS N-channel does on the board
The Infineon BSC050N03LSGATMA1 is a 30 V N-channel MOSFET from the OptiMOS series, built for low-voltage power switching.
Package and mounting — PG-TDSON-8-5
The 8-PowerTDFN package (supplier device code PG-TDSON-8-5) is a surface-mount power package with an exposed drain pad. The pad needs a good solder joint to the PCB copper for thermal and electrical performance — treat it as a thermal via farm under the pad.
It is ROHS3 compliant. No direct second-source alternate is listed in the record, but the OptiMOS 30 V family has several Rds(on) tiers — if the 5 mOhm is the fit, this is the part.