Gamepad button customization (PC)?

As the title says.
It would be nice to have some options. not quite big on ‘default’ setting on some games

You can use the Steam Controller overlay to remap buttons on any controller. Not just the Steam Controller. You need to enable it for your particular controller in the Steam settings, under “Controller” then “General Controller Settings.”
Might not be perfect for you but it could be worth experimenting with.