What more can i use M 83 for than
just for turnouts and uncouplers?
Have spare ones after i have going
more to digital turnouts

The manual that shipped with the early variants of the m83.1(=60831 =white) was a singular reference covering normal turnout/signal (pulsed pair) operation as well as the information needed to control ports individually

Later in their run, Marklin extracted the "too technical info" into a second manual that may be downloaded but is not shipped with the item
https://static.maerklin....944bb018ed1434541774.pdf

The same applies for the m83.2(=60832 = black)
https://static.maerklin....377f3df7281570606458.pdf

While the m83.2 introduced the ability configure(not operate) with mFX, it also had a significant feature over the m83.1 in that you could set it to 8=port mode , meaning you can distinctly turn each of the 8 ports on and off.
The m83.1 could do this but it was a toggle/pulse of the individual Red and Green aspects of an address.
e.g. pressing the button for 1G can toggle the port on, predding 1G again will turn it off.
note: as such the controller could not reliably know if the port was on or off.

When using the ports individually they had configurable settings, very similar to those of a locomotive decoder.
e.g. blink, double blink, mars, flicker etc