just right after my last firmware update (to 3.5), my NDX 2 is showing dramatic drop down of the wi-fi connection.
I’ve been streaming music via Qobuz -> Optical fiber -> Roon on Qnap NAS -> wi-fi -> NDX2 for over one year without any issue.
Nothing else has changed.
I checked wi-fi signal strength without founding any weakness.
Also try unplugging the NDX2 and the router. Then reboot the router, when that is settled, then power up the NDX2. Also restart the device the app is on. Have a cup of tea.