Malkin finishes in the top 30 on my list.
In his prime, he matched prime Crosby and prime Ovechkin point for point, award for award. Injuries took away his longevity, but he was always looked at as one of the Big 3 of his generation. More physical than Crosby and with a better hockey IQ than Ovechkin, Malkin is set to retire with the highest PPG among all Russians in the 40 year history of Russians playing in the NHL, ahead of greats like Ovechkin, Fedorov, etc.
I think you mean peak, versus prime. Peak, absolutely, as good as either of them, depending on the season or playoff run, or what you prefer.
Where he's actually quite weaker against Crosby and Ovechkin is his prime.
Ovechkin's prime is fantastic because he missed so little time, and although he wasn't as good throughout the rest of his prime as he was in his 3 year peak, he was still a machine of consistency with 50 goal seasons/rockets repeatedly.
Crosby's prime was fantastic, because although he missed a lot of times (partial seasons, or stretches of games), he never had a "bad" year. Above ppg each year, and can be argued amongst the best players in the league each season. His "worst" season is probably 2017-2018, but he was still 10th in scoring and saved the Pens season with an insane run when they were out of playoffs, to rise up standings, and then took foot off the gas at end. I certainly don't consider this a "bad" season.
Malkin's prime is a bit different. Still really good, but unlike Ovechkin he missed a ton of time and didn't churn out all those really strong seasons. And unlike Crosby, he does have some bad years in there. Crosby's lowest ppg season is 1.06. And because of league scoring being low that year, that's still a season where Crosby finished 2nd in hart (2016, won the smythe too). In contrast, 8x (including so far this season) Malkin has been at 1.06 ppg or below, including 3x below ppg.
Malkin is a great player, but there's a reason we're asking if he ranks in the top ~30-50/60 vs ~top 10 like the other 2. His prime was nowhere near as consistent as Crosby or Ovechkin. Still great, just not the same caliber