If updates is what you want, always get the carrier versions.. they get updates more frequently versus unlocked which pretty much gets ignored for some time (they still get updates, just very very slow).
The upgrade from the Pixel 2 XL really is just the flexibility of the extra cameras, getting that headphone jack back with Quad DAC audio, getting a micro SD card slot back, best audio recording because it has 3 omnidirectional mics on it (for content creation). If you really like the Pixel
camera software, just wait until the GCam gets ported over.. then it's really game over. The good thing about LG phones is at least you can download and change themes... stock Android you can't and it gets boring (I have a Google Motorola, default theme is boring and can't be changed, I think that material design is getting old).. BTW LG phones are cheaper too so it won't cost an arm and a leg esp. with phones costing $1000 nowadays. My 2 cents... Honestly the Pixel 2 XL is still a killer device.