Panic bought a Glock 45 gen 5 (non MOS)

I wanted a Glock 45 but won’t buy that V garbage. Most places sold out on them and the places that didn’t were selling the non MOS models for $699 or even $799. I luckily found through Bass Pro one for just $556.00 but it’s not MOS. If I decide I want to add an optic, can I just buy a Glock 19 MOS slide even if it’s not Glock original? Would a Gen 3 MOS slide work on it? I see them for $99 online. It’s Glock 45 Gen 5 so I don’t know 100% if that means it only works with Glock 19 Gen 5 parts ? Basically what is the cheapest and easiest way for me to get an MOS slide for it?