The idea that teams regularly win cups while not spending money on goalies is fake news made up by hockey fans. Since 2009 (using 2009 because contract data from before is a bit iffy on capfriendly), here are the starting goalies of cup winners and the percentage of the cap that their deal was when it was signed:
2009: Fleury at 8.82% of the cap
2010: Niemi at 1.46% of the cap
2011: Thomas at 8.82% of the cap
2012: Quick at 3.17% of the cap
2013: Crawford at 4.49% of the cap
2014: Quick at 9.67% of the cap
2015: Crawford at 9.33% of the cap
2016: Fleury at 8.33% of the cap
2017: Murray at 1.01% of the cap
2018: Holtby at 8.54% of the cap
2019: Binnington at 0.82% of the cap
2020: Vasilevskiy at 4.79% of the cap
2021: Vasilevskiy at 11.66% of the cap
2022: Kuemper at 5.52% of the cap
2023: Hill at 2.67% of the cap
The equivalent of $7 million today is 8.38% of the cap. 7 of the last 15 cup winners were paying their starting goalie basically the equivalent of $7 million AAV today or more, and 3 of the last 15 cup winners were paying their starting goalie basically the equivalent of $8 million or more.
I wouldn't go above $8.5 million for Hellebuyck probably, but getting him for anything less than that is an easy yes in my eyes. Especially considering how much cap flexibility they have going forward between their expiring contracts and the rising cap, the Penguins should easily be able to afford Hellebuyck long-term at $8 million.
7/15 paying sub 5% of the cap kind of says that teams DO regularly win by not spending a ton on keepers.