They’re similar, but Makar has WAY more help. In Ottawa, the best team Karlsson ever played on was a 44 win team (twice). Once was his rookie year (2009/10), when he was definitely not in his prime, and the other time was a garbage team that prime Karlsson dragged to the conference finals (2016/17), despite playing through a brutal injury (he was never really the same again after that - still had the puck skills but his skating never truly recovered). Makar has played on nothing but stacked Avs teams so far.
Makar is amazing, and putting up unreal numbers, but he has WAY more help, and it’s also a higher scoring era now. I’m not at all sure Makar outperforms Karlsson on the 2011/12 to 2016/17 Sens, which was Karlsson’s prime IMO.