As for bias, if you can't see that DF is obviously biased for MS, that probably says a a lot about your own biases. During the 360/PS3 era it was all positives for 360 in comparisons. Looking at any fine detail on PS3 games to show how they were inferior. When the PS4 was on top we got excuses for the XBO, questioning if resolution was really that important. An ever slight frame or two advantage on the XBO was more important than a increase in resolution from 720p/900p to 1080p. Usually ending each comparison by saying you'll be happy on either console, when before they were saying which console they recommended to get the game on. The 2nd the XBO X came out, it was here to "save the day."
Now we jump to this gen. DF were helping spread the FUD about PS5's variable clock rate, even having a flawed comparison using RDNA1 chips. When MS showed off their poor looking flagship title, Halo Infinite, quickly they had an excuse vid out, claiming most of the problem was a lack of raytracing. When people pointed out many other things, Alex said he was just too tired to go into it all. Keep in mind, this was just after zooming in really close on PS5 footage to show the raytracing reflections were lower quality or were missing objects. And now after we've had a few next-gen comparisons where they seemed pleasantly surprised about PS5 outperforming XSX, in this video they sound more troubled by it. It's almost as if they either realize that they shouldn't be excited by a system punching above its weight or they were told it's something they shouldn't seem excited by.
Just ask yourself, where are any of the videos making excuses for the way any game performs or looks on PlayStation?
Yeah, they've been expecting Series X to have noticeable advantages but so did nearly every other person in this industry prior to the launch. And now that they're actually able to test the machines, they are indeed giving PS5 credit. On most sites, the understanding is that DF has placed PS5 at or above Series X in all of their comparisons so far.
Regarding Dirt 5, I don't blame them for choosing their words carefully. 1) Because toxic fans are ready to question and attack them if they're even slightly too positive about one of the consoles. 2) Because they've still only tested a handful of games which aren't enough to conclude anything. If PS5 keeps punching above its weight in the following months, they won't hesitate reiterating it.
They're providing this service for free for those interested. No one is forced to follow them or see their videos. Personal attacks are never justifiable (not saying you're doing that).