I reckon that difference is something of concern to top end professional photographers 'as a general principle'. However I would be surprised if you found Mirrorless low light performance an issue. Mine manages perfectly well to capture low light images just to get a record of something. To get quality artistic low light images will require a tripod as even though the image stabilisation allows me to had hold down to 1/30th second with care, there are times when slower speeds are needed. Much the same would apply to DSLR's I reckon. I suspect any difference might be hard to discern to any but the very experienced photographer. As yet I haven't tried much of this, but the remote control will help when I do. I used that photo of the car above 'cos I know if I had tried to take it with my old Canon (Superzoom) I would have had to have taken it on a far slower shutter speed on a tripod, not just 'clicked it in passing' as I did & it would have still been grainy. I reckon it's reasonably clear for a shot requiring ISO6400, & the image in the EVF when taking wasn't problematic at all.
You can drive yourself nuts (well I can) reading camera reviews. There are so many fantastic cameras out there these these days minor issues tend to get focussed on (pun intended) It wouldn't be too hard to find reviews online to contradict or dismiss the concerns raised in the blog you linked to.
For me Mirrorless won out over DSLR as I wanted a quality camera without bulk & weight & the mirrorless options were way above my amateur skill level, giving me 'room to grow'. I have no doubt that it is possible to buy cameras which may do some things better, but if the weight & bulk means that they get left in the van it defeats the purpose. Your priorities will be different.
I have zero regrets about my choice & as yet have not found any boundaries that I have found limiting. That may come, but the same could be with any camera. I'm looking forward to learning a lot more about landscapes & lens choice out in the deserts.
Bottom line is that if you buy any modern 'prosumer' camera whether DSLR or mirrorless you will get something pretty good & any shortcomings your choice has will only become apparent with experience, & by the time you have gained that experience you will be ready & better informed to purchase it's replacement.![]()