Can you explain more about limiting the frame
Just print out a maximum of 250 samples, even if you have more. You need not start at the beginning of your data, you could just start from 250 from the end. Or indeed any other position.
You don’t want to print the first bin anyway because that has data that will not change.
I choose 110k baud rate
Bad choice go as fast as you can.
I know, serial plotter adds new values to the last column which is not okay for me
No it adds them to the first column and shuffles the rest over to the right. It is what you want.