While 1.0 mm wide lines are fine for a 0.4 nozzle, you actually can’t go wider than that - it’s the max. at ~0.2 layer bc math (see here, the source is libslic3r documentation IIRC). Bambu Slicer doesn’t even allow more than 2.5x nozzle size unless you fiddle with the extruder settings. Doing so, you “can” go wider but the shape of the extrusion will not be predictable so quality will plummet.
For a 0.8 nozzle, the max. width is 2.0 mm provided the nozzle flat size is 1.6 mm and layer height is 0.4.