From looking at the funding options seems like the simplest way to send #Pixelfed a one-time donation is this link:
https://opencollective.com/pixelfed/donate?interval=oneTime&amount=20&name=&legalName=&email=
Would also encourage becoming a recurring subscriber, using any preferred method, but now is the time to rush them some money to tackle this wave.
Good luck Dan! We are pulling for you!