You'll be fine with the LC250 all around Germany. Your biggest challenge will be the parking garages in larger cities.
Cars like the Audi Q7 or the BMW 5 Touring are pretty identical when it comes to width and length of the car and they are equally feasible.
Unless you're going for those true MURICAN trucks like the F-150 or the Ram 1500, cars all stay within a certain size range that works well all around Germany. That's basically 2m wide by 2m tall and around 5m length.
This site is super neat for a visualization:
Audi Q7 2019-present vs. Toyota Land Cruiser Prado 2023-present
Wonder if you'll be able to SOMEHOW sell that IFORCEMAX variant in Germany before you leave. Toyota is only offering the diesel here - recently in the hybrid version - the petrol engine should be pretty rare around here.
I don't see any fundamental issues with the emissions when planning on driving into these protected city zones but also not sure how this is handled for US staff import cars.
Used car prices in Germany are pretty dismal - check out mobile.de for a preview while you still have a chance to maybe bring a second car over from the US? Not sure if the situation over in the US is any better.