For one side, Gamers Nexus seemed to be quite stable in views and subscriptions and, according to Social Blade, the last week saw quite a dramatic increase in subs, which could be cast as a shadow on their motivation. Besides, I think he was butthurt with the comment against his channel regarding re-using data
I don't get this, what's wrong with reusing data if it's still valid and you can verify it's the same test procedure? 
New games and cards appear. Need new drivers and game patches to work properly. So the tests with older versions could be invalid. Some games are heavily patched, such as Microsoft Flight Simulator, which saw dramatic (100%+) increases in performance over its lifespan, but also erratic behaviour (poor performance only fixed by a system reinstall).
I honestly believe its not easy to properly benchmark. Steve from HardwareUnboxed said its not rocket science, but it is very tedious.
LTT wants to boast about automations, but then still is able to post wrong benchmark data. Some of the benchmark numbers swapped (e.g. Intel Arc A750) could be with raytracing on or off, which also has dramatic increases.
The other components from GN I don't agree with at its core. Forcing an experiment outcome is IMO still a wrong approach to testing. Because that's the vibe I got from their video. Each test should be ran under the same conditions.
E.g. a 300% increase between 4090 en 3090 is dramatic, but we have seen HardwareUnboxed test 8GB cards on high resolutions, and they show greater-than-expected performance retardation because of VRAM limits. Now VRAM limits cant be at fault in the 4090 benchmark (as a 3090 en 4090 both have 24GB VRAM), so that point is still valid.
But for other cards.. I don't necessarily agree. The seemed to have been pointing to different charts for their GTX1060 example ("Max settings" vs "Ultra + Vulkan"). GN forced a conclusion "none of the other cards really moved" => Yes, that could be because Ultra is probably Max settings, BUT choosing between DirectX(industry standard/default) or Vulkan rendering could favour manfacturer A,B or C more.
I think every reviewer would do benefit if they will write down the project and test run on each chart.
And then there is the issue the part variance is huge:
https://youtu.be/dGbW7orZS-ATLDR. 13x AMD Ryzen 7600 tested. CB23 MT runs in range 13.6k-14.4k. Clocks 4825MHz - 5075MHz. Load temperatures 79C - 88C. Load power 112W - 126W. Game FPS 60 to 86(!). FPS/W: 2.89 to 4.26
That latter has a 41% improvement on the same hardware bill of materials.
Representing a tight cluster of measurement data based on just 1 (or even a handful) CPU or GPU under test is also misleading. That's what GN advertizes in all their charts.