Assistance with Pixhawk (UAV setup) ArduSub (Pixhawk 2.4.8, Mission Planner)

Job ID: 33804531

Budget: $15 – $25 USD

ArduSub 4.0.3-FIRMWARE_VERSION_TYPE_OFFICIAL
Pixhawk 2.4.8
Mission Planner 1.3.77 build 1.3.8110.38294

It is needed to set up a depth sensor.
I've connected the BMP280 external pressure sensor connected. There is a constant exchange between BMP280 and Pixhawk.
This can be seen in the Mission Planner in the Status tab (img 1.png). As you can see from the picture, the HUD has the label "Bad Baro Health". In Config Mission Planner such settings (img 2.png), and after reboot
Pixhawk parameters BARO_EXT_BUS and BARO_PRIMRAY are not saved and are set to 1 and 0
respectively. It is not clear where the depth should be displayed and how to select the "depth hold" mode.
In Action Mission Planner, it is impossible to set any mode with the "set mode" button, due to an empty list
(img 3.pnf)