are you really saying that professional troops are less effective than untrained conscripts who really don’t want to be there?

Firstly... there is absolutely no rule that says conscripts have to be untrained, just like there's no rule that says a conscript wouldn't necessarily want to be there - but that's irrelevant to the question at hand.

More importantly, yes - a citizen army can be more effective than a professionalized one. Napoleon Bonaparte's armies proved that to the world to such a degree that military theorists of the time literally thought the professional military obsolete. Of course, the problem with a citizen army is that you have to animate the citizenry with a cause that can actually be justified - kind of a difficult thing to do if you're waging colonialist wars that only benefit the wealthy half-way around the world. Which is what a professional military is good for - that's why the US didn't experience the same level of revolt in the ranks during the occupation of Iraq and Afghanistan as they did during the war on Vietnam.

but a professional army would have been much more effective

Ukraine did have a professional army at the start of the war - almost all countries do. Not even NATO would be able to defeat Russia with a purely professionalized force - that's pure fantasy.