This is under asking for sure.
If the Leafs move Marner to Ottawa, it would probably be for one of Brannstrom/JBD (I think both can play the right side) + one of 3rd or 5th OA + Formenton + More. It would be an astronomical amount to move a 90 point winger

not astronomical if their hand is forced and they have to move him to make changes

But it isn't. They know they can field a competitive team with or without him. I doubt he will be traded.

there was nothing competitive about their game, the word "compete" isn't in their vocabulary
if they go a 5th year with no playoff success someone will be traded

Their hand isn't forced. Marner won't be moved. I will bet anyone his full salary on that. He was actually good in the series. A bit soft and invisible in game 1, but the rest of the series he was generating offence. It's not his fault the guys he passes to in the slot couldn't bury it (Matthews, Tavares)... if those goals go in it's a whole other story we're talking about. They were high danger chances that got stopped or hit the post. Add in that he played good defence in the series and their hand definitely isn't forced. He's not getting moved.

Marners contract length and cap hit make the price close, but it needs a little massaging.

Swap the NYI 1st for 5OA, and take out Formenton.

That said, almost no chance Marner gets dealt. I think Nylander is more likely