Slow and jumping file transfer speeds on Mac

[MarcinNB]

hello,
Since the beginning of using mac I have a problem with file transfer speeds. Sometime after computer startup / several wakes from sleep trasfers from NAS to computer disk (from computer to NAS too) drop dramatically. In comparison, after a reboot the transfers reach full capacity, reaching transfers around 150-280mb/s. However, some time after the reboot, transfers dramatically slow down and reach from 0 to 60mb/s. Does anyone know what the problem could be? I think it is a problem with the configuration of the computer, but unfortunately I have no idea what to do.

My hardware:
Mac Studio M1 Ultra - 10G
QNAP-TS-364 - 2.5G
QNAP QSW-1105-5T Switch - 2.5G