You can use DP 1.4+DSC -> HDMI 2.1 adapters. 4K, 120 Hz, 10-bit, 4:4:4 with HDR is possible with these. The only feature that does not work is VRR which is unfortunate but not a dealbreaker for me. I'd rather wait for GPU prices to go to sensible levels than buy a slightly faster GPU than my 2080 Ti at nearly double the price.Biggest advantage is you only need an HDMI 2.0 compatible GPU for the Alienware. To get more than 60Hz on the LG you need a 3000 series card.
Via HDMI 2.0, the LG OLEDs can do 4K 120 Hz 8-bit 4:2:0 without HDR. Which is perfectly fine for SDR gaming.
But yes, the Dell does make connectivity more straightforward.