There is a machine at our local makerspace that goes much faster than my Lowrider. More than twice as fast I’m sure. I found it a bit alarming to be honest. I can make mistakes plenty fast enough at 8 mm/s 8^)
This is why I’ve been using a 1/4" bit. The 1/8" is probably fine for the 1/2" ply, but just seems sketchy in 3/4". EDIT to add that the 1/4" clears chips out of a deeper kerf MUCH better than the 1/8"
I think the 5mm DOC is probably my personal comfort limit. The router starts to sound like it’s laboring that little bit too much at about 6mm. Also, the materials I’m working with are never perfect. The plywood may be bowed off the table a bit in places…perhaps a touch thicker in some spots, etc. This can already lead to cuts being a couple mm deeper than intended in some areas.
A couple of mishaps have me thinking that my Lowrider may start skipping steps at about 9mm or so DOC with this bit/feed rate/etc. and I like a little margin.
The machine rigidity factor is interesting and plays into this as well. Let’s say your wider machine flexes down 1mm at mid-span do to the weight of the router dust hose, etc. add that to the variables mentioned above and you might be pushing that limit. You may be loosing some precision as well, because now your ARE loading up the lateral axes as well and your gantry might start flexing that way too.