paying account upgrade via paypal

I'm considering to upgrade my account. And recently I see danbooru can accept upgrade payment from Stripe. Can't danbooru accepting the payment with Paypal ?

It's not Danbooru's fault, it's Paypal's. Paypal doesn't allow its services to be used for the digital distribution of sexually explicit materials. Sexual content makes up only a small fraction of the art on this site, but it's enough to make Paypal not want our business.

is there any other way to upgrade account aside from paying using Stripe?

Another user can gift you an account upgrade. That user will have to pay via Stripe too, though.

Otherwise, no.

The longer way is to continue uploading, tagging, and translating until you're upgraded to Builder, which enables the same privileges.