There is supposed to be a circlip that keeps the end of the shaft from popping out of the bracket.
It appears your circlip might be AWOL.
You might not have full rack travel if there is too much slop in the pivot bushing.
With the engine off, have a buddy depress and hold the accelerator pedal all the way down.
In the engine compartment see if you can rotate the throttle shaft to provide some additional rack travel.
If you can get more rack travel even with the accelerator pedal fully depressed, you might need to adjust your linkage and/or replace the whole pivot bushing or perhaps just the circlip.
The pivot mount MB part number
123-300-13-40 is available from the forum sponsor.