So, now I've switched from DigitalOcean completely to Vultr. To be honest - mostly of price, cause it's a bit cheaper. And accepts debit cards.
And also had a chance to set up HA on this cloud provider followed on this article.
But some additions to it for complete algo.
1. Order a BGP with support ticket with Vultr provided AS.
2. Purchase a Reserved IP address, but not assign it to none of instances
3. Order 2 instances in same location
4. Set up network on both instances according to article.
4.1 Use Reserved IP address as dummy1 interface IP
4.2 Use /32 subnet mask regardless on what you see in Reserved IP settings.
4.3 Use Bird settings from server instance BGP page (BGP configuration link) not to mistaken with AS addresses and passwords.