In most cases, speaking from personal experience with a number of Merchant Providers over the past 15 years, it’s not specifically that you’re suspicious. A red flag could go up because your bank is telling the merchant that the card you’re using was just used elsewhere, in another state/country and as such, the merchant denied it on behalf of the bank. Some merchants are far more strict that others; some are far more lax than others (and honestly, those are the ones you should be worried about).
The fact that DigitalOcean does flag accounts, little or lot, means that they do indeed care about what’s going on; both with their customers and with their network. As such, once this passes, you’ll be in good hands (I’ve been using them for 2 years now - no complaints).
I know it’s a pain, though I look at it this way. If this were my business, would I rather flag and actually interact with the potential customer or simply throw more automated junk at them (i.e. click this, respond to that, enter your phone number to get this code and enter it within the next 60 seconds etc). Just check your email from time to time to check if you got any new notification, but give it a little bit of time. They will probably have it done in the next few hourd