There is a restriction to 25 people max, using the people picker control within forms (classic and responsive).
As there is no limitation within Sharepoint concerning people columns:
1. what is the use of that limitation?
2. where/how can I get rid of it?!
Solved! Go to Solution.
Found it. Simply within the settings of the control.
But then there is still my question - where does it come from? Why 25? Any resons for not exceeding this threshold?!