I caved and got a Defender. While I have been leery about the Defender due to LR's reputation for reliability, I did quite a bit of research and realized the the Defender does not tend to have anywhere near the issues that its Range Rover siblings have. I ended up finding a nearly fully-loaded 2020 Defender locally for about $55k with 30k miles on it. Yes I got the warranty! Seeing how I'm going to be overlanding on concrete for 99% of my trips, I wasn't worried about the loss of articulation.
As far as the GX goes, the sticking point I kept coming back to was the interior. Exterior is amazing on the GX but the interior felt a little cramped and boring. Also I had recently ridden in a Rav4 and the infotainment system was as boring and simple as the Lexus's is. For $70k I wanted to be "wowed" and the GX just didn't seem right for me for the price. I'm not knocking it, I'm sure it's going to be a great truck! I just hope Lexus steps up the interior in the next few years because it's already dated inside and uses tech that's been out for a few years.
The Defender prioritizes passenger comfort; back seat has more leg room than the Lexus and also has full comfort features. It is full-featured and doesn't restrict the driver at all (for example you can use the cameras at full highway speed). On top of that, I absolutely love the interior design language. I'll be happy to answer any questions. I'm still intrigued by the GX so I'll be lurking here for a while.