You're not getting a lot of responses so I figured I'd offer the little that I can.
I have not used Krita for pixel art, moreso regular digital painting, and I came from using Photoshop. Once I got used to the different control scheme, I enjoyed it quit e about more for digital painting than Photoshop. It's free and the learning curve isn't that steep so it's worth a shot I think
Tbf if you're drawing exclusively/primarily pixel art I think libresprite is better - because it is more focused on it/made specifically for it.
Krita is an all-can-do program more a-kin to photoshop (but krita is better imo), it can do pixel art too, but it has a lot of other options, bells and whistles because it was made for digital art as a whole.
I have tried both, Libresprite is nice, but I am more used to working with Krita, alhough my laptop really dislikes it and heats up. Was not an issue when it was booting Linux so an OS issue I guess.
Libresprite is obviously more plug and play experience.
Krita has a decent pixel art support, but requires a bit of setup. Some tools have Antialiasing option in Tool options docker, so you may play around with that, if your selections and fills are getting messed up. It has some pixel brushes, but if you decide to stick with it for a while I would recommend making some brushes and patterns for pixelart on your own as well, just for the sake of convenience. Also make sure to customize your dockers (UI).