Agree with this, because I own both (X4 is a recent addition) - they work exceptionally well in combination because their focus is so different.
If I want to do some planetside exploration - and honestly, even though despite jumping pineapples and floating land mass sillyness the way that is implemented is so much better than how it's done in Elite. Never thought I'd say this but once you accept the art style and the unrealistic physics etc. it's actually a great exploration game, as the variety is sufficient enough to make a planet feel different (unlike the limited and copy-paste planetary features in Elite), and how it's tracked in its "codex" equivalent.
While in Elite I often spend significant amounts of time staring at the screen twiddling my thumbs (or instead alt-tab out to the forum), I'm proper busy in NMS; there's so much to do and I keep getting distracted all the time. As a game, it's great, and I admit I never really gave it a proper chance because Elite was always my go-to space game first, though that has changed since EDO launched, and particularly patch 5.
I'm only about 5-6 hours into X4, and while it's true that the graphics don't "pop" as much as in Elite or even NMS, I do like the visuals nonetheless, and everything feels like a proper "lived-in" galaxy, even if it doesn't allow the same freedom as in Elite or NMS. NPC ships go about their business, you can frickin' land on another ship, or have yours piloted by NPC crew, you can stick to single ship flying a la Han Solo or build a massive fleet (that's my goal but I'm still at the Solo stage). The economy makes sense, there's EVA (although very basic), and on-foot stuff is optional (i.e. it's there if you want to but you're not really forced into it, feels more natural how it's implemented), travel isn't as boring and tedious as in Elite and you have various options (autopilot, travel-mode, NPC crew) to go from A to B.
And if you want -proper- ELW exploration, there's always MSFS2020