As for the TCAS settings, I thought it was possible for those to be changed manually
As mad_jock points out above, there is a common misconception that manually adjusting the display range somehow affects the range at which the generation of TAs and RAs occurs. It does not. Company SOPs or manufacturer recommendations may specify which display range should be selected by the crew during different phases of flight so that the selected display range is appropriate to the true airspeed during that phase of flight. In terminal areas it is appropriate to select a smaller display range while during cruise flight at high altitude, a greater range should be displayed. In effect, the displayed range should be varied so as to provide an opportunity for the crew to observe intruder aircraft well prior to the generation of a TA or RA while allowing the display to be decluttered by selecting a smaller display range in more densely populated airspace. I hope that makes some kind of sense!
In high altitude oceanic airspace it is normal to select maximum display range.