I'll open by saying as a non Pens fan, I probably wouldn't trade Marino for Garland. Because of scarcity of the position, the lack of in-house replacement, Letang's uncertain contract status, etc etc
But the bolded is a little deceiving and unfair. Garland has more or less broke into the league during this bloody pandemic, and has yet to really have a chance to prove what he can do over a full season. It should not be held against him. He's paced for some promising numbers, particularly last year on a middling Arizona team