He's only 27, I don't think you're going to see a guy in his 20s agree to a structure like that.
This deal will be what defines his professional earnings as a hockey player. It doesn't necessarily mean he's going to be unreasonable, but he's going to look big on that number. Discount deals are for older players
He'll be 28/29 when the new contract kicks on, and on an 8 year deal the final year he'll be 35/36. Shea Theodore's contract is an example of what I'm talking about, and a good value comparison to Boeser. Starts at $9.5M and ends at $5.7M, with a cap hit of $7.425M. That's a 7 year contract though and he's a year older, so to apply the same standard directly to Boeser you add an extra $9.5M year at the start and get a cap hit of $7.68M over 8 years.
Looking at various long term contracts signed for players approaching 30 or older, some or structured like the above while others pay the same for the duration. I feel like that's the biggest factor for a 'team friendly' contract these days, as a GM can easily just pay a guy the same amount right to the end of the deal and chances are won't be around to deal with it then.