The date from the GPSs is UTC and OpenPlotter gets this time ans set the system time. You should check the system time zone of your system: Menu > preferences > raspberry configuration > localisation > set timezone
If you do not have lat and lon is because you do not have a good sky view and your GPS is not able to get position from the right number of satellites. Date and time can be provided just by one satellite so you get only this.
Try to make work your BU353S4 GlobalSat and then try to make work the GPS / GLONASS under the same conditions. If you can't make work the GPS / GLONASS send me a private message and ww will replace your unit in case is defective but it would be strange because they are strong and none has failed yet.
If you do not have lat and lon is because you do not have a good sky view and your GPS is not able to get position from the right number of satellites. Date and time can be provided just by one satellite so you get only this.
Try to make work your BU353S4 GlobalSat and then try to make work the GPS / GLONASS under the same conditions. If you can't make work the GPS / GLONASS send me a private message and ww will replace your unit in case is defective but it would be strange because they are strong and none has failed yet.