I don’t think this “inserts” like you mean, one FX per insert point?
An Fx engine can be added to any/all inputs to varying degrees, depending on your channel send to that fx.
You can then send the fx master send to multiple outputs/mixes – you just have to add the fx return to the outputs you choose.
Eg.
Ch1 sent to Fx1.
Fx1 returns to LR and mix outputs at independent (master send) levels.
Any channels sending to fx1 will be heard in the fx1 return.
You don’t have any way of changing your inputs fx balance per send – you just get a summed output per master send.
Hope I’ve explained this properly!😉