Congrats on your purchase!
My view is that the credit card part doesn't matter much. I'd consider it in the sense that if a direct purchase codes as 4x and a resale purchase codes as 2x and capped at $7500 on a credit card, there is some extra value in buying direct - but it's 4% (~$1000) tops, and likely less than that...
I think you kind of have to separate measly PIT developer incentives from the credit card bonuses. If I want a new credit card with a bonus there are usually other ways to get it besides
DVC. For example, you'd literally get the exact same bonuses if you used the credit card and spent $30K on Marriott gifts card that never expire and can be used at almost all Marriott hotels over the next few years (or pick your favorite brand like Hilton or Hyatt). So if you can get the same bonus by buying something else that you will eventually use, then does it really matter? The credit card really has nothing to do with the DVC purchase.
Moreover, saying that those 330K points are worth $7K in travel rewards may also be a stretch. The "original" Sapphire reserve that I had/have for over a decade used to have a 50% redemption bonus on
all travel booked via the Chase portal but that perk been discontinued (existing card members keep it for 2 years). The new, more expensive, card has a "up to 2x points" travel boost but with a lot of qualifiers, implying rotating/changing/varying promos and categories. Time will tell if it's really 2x... (I highly doubt it)
Points Boost offers will provide eligible cardmembers with redemption values of up to 2 cents per point when booking with Chase points through the Chase Travel portal. This will apply to select hotels, including bookings made through The Edit, and airlines.
The main thing I care about are the current developer incentives. The "extra points" you mention are an important consideration if alternative resales are stripped but I can always time the DVC purchase to get the extra points, so it again comes down to current incentives to sway me to sell actual investments to buy a timeshare. And for PIT, the incentives are pretty bad and have been so since they started selling last year and jacked up the base price by $10 shortly thereafter.