Keep in mind that bandwidth bottlenecks can happen on both sides - depending on the peering that is chosen between Comcast and DigitalOcean, there might be a significant oversubscription between two peering providers that's causing this.
DigitalOcean might happily be able to push 10g to their next hop, but beyond that things are significantly more outside of their control. This is mistaken as 'throttling' a lot, but is actually just ISPs not investing in peering to handle their peak demand. Similar to the Netflix and Cogent issue that happened a couple of years back.
At times, I can get better speeds by tunneling or proxying using a DigitalOcean Droplet and downloading something from overseas than I can doing it directly. The path taken from my home internet to the DO Droplet uses different peering than my path to Europe, and the speeds are faster overall even though it creates more hops.
