I think we all knew PSL's were going to be a part of this. They're giving you the right to buy your seat, if you don't want it, they'll give other people the right to buy it. Other STH's and waitlist people are given a chance to upgrade for a cost - and PSL money doesn't get touched by the league or that 38% that the opponent gets. You're still given the first right of purchasing it.
If we didn't get PSLs? They would likely struggle with the P&L and their loan payments for the stadium. Probably head back in the direction of a cash to cap type team or they'd likely be operating in the red for a few years. Then you task people with saving you money, so you pay less for... training staff, coaches, scouts, literally anything that isn't touched by a cap. Yes TP could probably offset it by cashing out - but that isn't really how the NFL works.
As for financing? Inflation has been pretty bad in recent years so... interest rates are high. Easy example - If you borrow 100 dollars today and pay me 110 dollars in 10 years. In 10 years 110 dollars will be worth considerably less in tangible value than the initial 100 i loaned you. That (plus the obvious - im supposed to make money by lending money) indicates you need a considerably higher interest rate.