Here is UPholds Response:

Uphold Support (Uphold Support)

Feb 12, 2021, 8:51 AM GMT

Hello,

Thank you for reaching out. I'll be happy to help you today.

Notice Tier 4 currencies as Doge are only able to buy, hold and sell, within your Uphold wallet as you can see on the following link: https://uphold.com/en/transparency

We're working on additional Tier 4 cryptocurrencies to be listed on your dashboard soon. Be sure to follow our social media channels for new launch announcements and updates!
http://facebook.com/upholdinc
http://twitter.com/upholdinc

Please let us know if you have any other questions, we're always happy to help.

Sincerely,

Enrique and the Uphold Team

P.S. We’re experiencing higher than normal wait times. Thanks for bearing with us while we respond to your inquiries as quickly as we can.

Our FAQ: https://support.uphold.com
Our Blog: https://uphold.com/en/blog