Unless your grass is short and dry, and the mower has a slow forward
speed, then forget it.

I have a top of the range Honda HRX21 that has a MicroCut Twin Blade
Mulching fitted.

This, as is the case with all other mowers with mulching fitted, are
no good if the grass is long and or wet. Even if the grass is slightly
damp, you end up with chewed up grass lumps, all over the lawn.

As I cut grass as business, the only one reliable method is to bag
it.