Don't know if this was posted already, didn't see it on the first post - but BJs currently is offering 5% off (a 1% increase over their normal 4% off) Disney Gift Cards. A $500 gift card is $475 instead of $479.99. Combine this with the PayPal 5% back on Discover and you're paying $451.25 per $500 gift card, and you can grab an extra $50 and $25 gift card to get up to $1500 on the 5% back (if you haven't already used it). I've combined this with Rakuten and got 1.5% back on my BJs purchase (unfortunately, I did this before the 5% off, so I only got 4% off from BJs). Almost 10% off (9.75%) before Rakuten's cashback.
Not as good at the BJs Black Friday 6% back - but normally you can't combine this with the Discover 5% back during Black Friday - and you're instead combining with a standard cash back, of ~2% or so and if you're lucky a Cash back site that offers 5% for Black Friday.
Wish BJs was offering bulk discount purchases on Disney GCs again but they haven't offered than since early 2020.
To extend your cash back, take the 5% discover cash back balance and buy Happy gift cards at a 10% discount (occasionally 25%) through Discover's redemption program. As long as you pick one that's a "Enter Credit As Payment" that card can then be used at a store to buy a Disney Gift Card. Effectively giving you a 10-25% discount on the disney gift card.
If you have a Wells Fargo credit card, happy cards are also 10% off there right now as well and can be used to do the same with their rewards program. Chase also offers them, but it is not discounted right now - was last month.