ufw "command not found"- but as the root user!

My Debian 11 VPS is running now for about 2 weeks- and today I just wanted to analyse, why my traffic is ~70GiB (counted by bashtop). So somewhere in the net I read about nethogs, that this could help. So I installed it with my non-root, but sudo-grouped user.

sudo apt install nethogs

I couldn’t run it.

So I switched to the root user with

su

It still didn’t worked.
So I just wanted to check the most important thing, the ufw.

ufw status

Output: command not found

---

So …

1. ufw is installed
2. but it works if I execute it from the full path with

/usr/sbin/ufw status

But I want to know also, if the incoming traffic is really blocked by default until now:

/usr/sbin/ufw status verbose

Output: ERROR: problem running sysctl

Something is really fcked up … I don’t know why? The last thing I did 2 weeks ago was installing kuma-uptime with the kuma_install.sh
After that I didn’t tried ufw. So. my $PATH seems to be not working correct- even as the root user.

I’m not an expert, but this is how my bashrc file looks like (from the root user):

# ~/.bashrc: executed by bash(1) for non-login shells.

# Note: PS1 and umask are already set in /etc/profile. You should not
# need this unless you want different defaults for root.
# PS1='${debian_chroot:+($debian_chroot)}h:w$ '
# umask 022

# You may uncomment the following lines if you want `ls' to be colorized:
# export LS_OPTIONS='--color=auto'
# eval "`dircolors`"
# alias ls='ls $LS_OPTIONS'
# alias ll='ls $LS_OPTIONS -l'
# alias l='ls $LS_OPTIONS -lA'
#
# Some more alias to avoid making mistakes:
# alias rm='rm -i'
# alias cp='cp -i'
# alias mv='mv -i'

and the .profile file:

# ~/.profile: executed by Bourne-compatible login shells.

if [ "$BASH" ]; then
  if [ -f ~/.bashrc ]; then
    . ~/.bashrc
  fi
fi

mesg n 2> /dev/null || true

and this is the path to ufw:

ufw: /usr/sbin/ufw /etc/ufw /lib/ufw /usr/share/ufw /usr/share/man/man8/ufw.8.gz

and that is my echo $PATH:

/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games:/snap/bin

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Hope this is enought and someone could help me please, you’re my last hope. Otherwise I have to switch to ubuntu, maybe ubuntu behaves better. I hope, I can solve the problem with your help. It would be great, if someone could tell more or less what I have exactly to do now.