So you don't understand how contracts work with a rising cap...
Brady signed his contract after the 2020-2021 season where scored 36 points in 56 games (53pt per 82 game pace). The first year he was at $8.33M before it dropped to $8.2M. I'll use the $8.2 just for fun. $8.2M was 10.06% of the $81.5M cap ceiling that first year.
10.06% of next year's projected $95.5M ceiling is $9.61M. Knies scored at a 61 point per 82 game pace, so there's no discount for him being worse than Tkachuk currently as his pace is better than Tkachuk's was when he signed the contract. Tkachuk's extension was also 7 years. 8 years would represent a bump in cap hit for buying an extra UFA year.
Probably looking at $9.75M AAV if you think he's the next Brady Tkachuk (1st line power forward) and insist on an 8 year extension.