I wouldn't expect too much difference in sales right now. Both are selling what they can manufacture. Neither should have a major manufacturing advantage.
That said, whether it's Xbox Series or PS5, if you have crashes in multiple games or artifacting, be prepared to trade your launch unit as soon as you're able to. My Scorpio One X had periodic crashing issues which I ignored because they weren't super frequent. As the gen went on and games got more demanding, it became more frequent. There wasn't even widespread issues with the One X. These things usually get worse, not better. I regret not acting early when under warranty. Nobody should hesitate to trade in launch units. Regardless of which one is worse right now, they'll all be worse in terms of reliability than later batches.
Haven't noticed any artifacts on the Ps5 thus far. Hoping it stays that way. Have had 2 software crashes and one mandatory database rebuild.