Why are settings from /etc/network/interfaces ignored (and how does using NetworkManager affect this)?

Question

linux

I needed to set a static ip. Faced with the fact that the settings from the config specified in the question for some reason are not applied. Network Manager is used, I sin on it, but I'm not sure. ifconfig output and config contents, in the attached screenshots.
If this helps, then in cases where everything worked, I installed the complete system (from DVD1 with a graphical environment) And now I installed with netinstall, then rolled up i3wm and started using it.
Debian 10x64

Screenshots (output of ifconfig and contents of /etc/network/interfaces )

Answer 1

NetworkManager Text User Interface - nmtui, a network configuration utility with an intuitive GUI. In rhel, you could specify in the interface settings not to touch it with NM, I generally demolish it in debian (for a server in statics, this service is superfluous), but in general, try turning off and disabling the NM service via systemctl

Answer 2

man NetworkManager.conf
But it's big, so it's better, as already said here, to use nmtui (I don't suggest nmcli ;-)), or even install/run nm-applet or nm-connection-editor