Is there a workaround to use of bash via adb on LineageOS17? I try to login in my device directly vith
adb shell bash -i

It kind of partially works, because I'm logged with bash, but the terminal loose completion.
The error I get:
$ adb shell bash -i 
bash: cannot set terminal process group (-1): Not a typewriter
bash: no job control in this shell
mydevice / #

Is there something possible to do it properly without errors ? I don't have su installed.
The error is expected. adb shell by default doesn't allocate a TTY (terminal) which is required for interactive session. Instead use:
adb shell -t bash -i