Doesn’t install on NodeRed based on Raspberrymatic (Homematic)

[hodiet]

System: ccu3 with raspberrymatic 3.71.12.2023.10.20(rpi3), NodeRed (RedMatic 7.2.1)

Tried to in install with nodered internal palette management: failed, no output, no reason
Tried on ssh command line (root user),

npm install node-red-contrib-tplink-tapo-connect-api
(from https://flows.nodered.org/node/node-red-contrib-tplink-tapo-connect-api)

failed with error: no such file or directory: /root/node_modules

this is correct, because /root is a read-only file system

my question, did anyone solve this installation issue already?

[hodiet]

The installation command line have the option --save-prefix=~
That is probably wrong, because ~ points to homedir of current user, which is root. What directory should be the installation directory of a nodered add on?

[hodiet]

Hm, no. Even with option --save-prefix set to /usr/local/addons/redmatic/var/node_modules
the error remains the same, it's still complaining that /root/node_modules is not available.
Any ideas?