Just a thought. Given the fast-growing climate of censorship here in the UK, it’s probably best for a UK user to change their DeviantArt setting to read ‘United States’, ASAP. Ideally you’d do that once you have your VPN set up, and you appear to be surfing from the USA.
This is because DeviantArt are bound to be next in terms of having to block/remove all their UK users.
I find I can get to DeviantArt with the Mullvad VPN without any problems at all. Changing my region setting, while using VPN USA connection, didn’t trigger an email challenge.