How to use kstart5 in a non-trivial way

[Jerome Yuzyk]

I used to use kstart to open a few GKrellM windows on all desktops.

With Fedora 31, kstart has been replaced with kstart5.

Which I can't get to work.

Here's what I get when I subsitute kstart5 for kstart:

1015 watch  kstart5 --window 'gkrellm_S-bss-gate' --alldesktops gkrellm -f -s 
192.168.0.22 -P 19150 &

1016 watch  kstart: Unknown options: f, s, P.

Quoting the command doesn't work.

kstart5 --help says to use:

  --!+command                Command to execute

but that doesn't work.

Googling only gives examples of restarting plasmashell or commands without 
parameters.

So I'm really stuck. I can't even find source code to see how it works.

Does anyone here use it?