My neighbor owns the newest X5 45e (he traded his 1-2 year old one for it because they doubled the electric motor output or something), so I've driven it. It's a gorgeous car inside and out, but as it doesn't have a third row, it didn't meet my needs when we were shopping for my wife. I realize this isn't exactly what you asked, but I figured I'd lay out some of what I feel are the important differences in the hopes it might get you thinking about how far apart the two cars are.
45e pros:
-The interior is true luxury. Getting in an X after you've been in a 45e makes you understand all the people that say Teslas aren't luxury cars. Material fit and finish, tactile experience virtually everywhere, and ergonomics are just so much better than in the Tesla it's hard to compare them.
-Buttons, switches and knobs. This is probably polarizing, but even though I don't generally mind managing everything with a touchscreen and couple of buttons on the wheel, I prefer more controls.
-Purchasing and dealership experience. Not much to say here; it's a traditional car sales model, so the dealers give a crap about their customers and BMW doesn't drop the price of their vehicles 30% over the course of a year routinely (even though I've only ever benefited from this as a 3-time Tesla owner)
-Not fully electric. This might be a con, but depending on your use case, i could see it as a pro also. The added range and ease of refueling on road trips in the 45e are nice to have, especially when you get the plug in usage for daily commute.
-Standard tech that works. Stuff like auto sensing wipers, backup cross traffic sensing, top down camera views for parking, etc. Everything they promised when you bought the car is already there and works, as opposed to Teslas empty promises (explicit or implicit).
MX pros:
-Technology. Like the luxury component for the 45e, Tesla is so far beyond the competition here it's almost difficult to compare them. Spotify/netflix/youtube integration, a GPS system I actually use (unlike literally every other built-in GPS in a car), huge display, insanely useful phone app controls, falcon wing doors, auto open/closing front doors, even minimal stuff like geofenced garage door opening and ride height settings.
-Performance. The 45e is what I'd call a quick car, but even when you max out the power settings and really hammer on it, you're still only getting part of the power of even the base level MX. Tesla has truly ruined me on car buying because they give you performance that beats other manufacturer's top of the range cars for entry-level prices. With such a small, flat hierarchy of cars in their stable, they don't need to worry about less expensive models eroding sales from their halo cars. BMW, Audi, MB, Porsche all do, and it shows. Not just straight line performance, either. The MX is not built like a traditional SUV and you can feel it when you drive it. I wouldn't call it nimble by any stretch, but it doesn't feel like driving a large, top heavy SUV, either.
-Capacity. Since the Teslas have been designed from the ground up as EVs, you get to use some of those little spaces that aren't being used by traditional ICE components. The 45e is still very much a ICE, and even the iX (and all of BMWs EVs) are still using their gasoline-equivalent chassis. Despite the fact that the 45e is a much larger car on the outside, I felt the MX actually gives a good deal more space on the interior.
-Sound system. I'll say it now - the sound systems in modern Teslas are the BEST I've ever experienced. Better even than the B&W systems in BMWs and B&O systems in Audis. I read an article by an audiophile awhile back that was talking about this, and how its the result of Tesla's horizontal integration of components. Since they control everything about their constituent components, they're not dealing with whatever crap they got from B&W or B&O (which, as someone with B&W speakers at home, are nowhere near the real thing) or other supplier just to get that badge on there. The MX sound system is amazing.
-Tesla charging network. This one speaks for itself. I suppose it's less of a point since the 45e isn't a true EV and you can fuel it with gasoline, but still.
These are just some of the differences. It really depends on your priorities. I love BMWs, and have owned more than 10 of them over the last decades, but the advantages they offer just aren't as important to me as those of the Tesla. YMMV.