I’ve found that proper tubeless ready tyres on proper tubeless ready wheels are actually quite easy to do. It’s the bodges that are a pain in the backside.
I did the Schwalbe G ones (so a smaller air volume than an mtb tyre, admittedly) on my ‘gnarmac’ bike a few weeks ago and they both went up on the first stroke of the pump. Normally you need to pump quickly* for a few seconds before it ‘takes’.
It helps to leave them inflated with a tube at quite high pressure for a bit to get the tyre the right shape for the rim.
*Swiss Tony, beautiful woman, etc etc.