Quick answers
What button is Focus Mode in Monster Hunter Wilds?
L2 on PlayStation and LT on Xbox, held rather than toggled by default. On PC it is a mouse side button for melee weapons and Left Alt for ranged ones. All of those are remappable, and the hold can be changed to a toggle in Options › Controls › Aim/Focus Mode Controls.
Should I set Focus Mode to toggle?
For most players, yes, and the reason is mechanical rather than preferential. A held analog trigger is a state your finger has to maintain while the rest of your hand does everything else — and it can dip below what the game reads as down without ever coming off. A toggle removes that failure mode completely. The setting is made separately for melee and ranged weapons.
Why does Focus Mode keep turning off mid-combo?
Almost always because the trigger relaxed. L2 and LT are analog, so 'held' means above some threshold, and a finger under load does not hold a spring flat — it sags. When it sags past the threshold, Focus Mode ends, the attack goes somewhere else, and it feels exactly like mistiming the swing. The bench on the hub page reads the trigger as an analog value and shows you the shape of your own hold.
Do all weapons use the same controls in Monster Hunter Wilds?
No, and that is why this entry does not publish one flattened button list. Fourteen weapon types each have their own scheme, and the same button means different things depending on what you are carrying. What is shared across all of them is Focus Mode, which is what this page is about.
Is Monster Hunter Wilds better on controller or mouse and keyboard?
For the Focus Mode problem specifically, a keyboard or mouse button removes it: a digital button is down or it is not, with no analog value to sag. A controller trigger has travel, and travel is where holds fail. That is a narrow claim about one input and this page will not extend it to the rest of the game.