Quick question on taxes. I filled out an extension for 2020, and I'm just getting around to filing my taxes. I'm owed a refund just under $1200. I want to go all-in on I bonds this year since the rate is attractive. I already bought the $10K of I bonds I can through treasury direct, and I'd like to buy the $5K that I can with my tax return. That means I would need to prepay ~$3800 before filing my taxes. Is there a way to do that?
On the direct pay website, it appears that I can only make estimated payments for 2021, or actual payments for 2020.
Thanks in advance.