You may be able to improve your connections, but performance is not related to your account or subscription level.
In the best case scenario, and what we always aim for, ZeroTier connects peer-to-peer and none of your network traffic travels through our servers. This means transfers go as fast as your CPU & network can compress, encrypt and send packets, and how fast the remote end can receive them.
There are some cases, such as hostile NATs & firewalls in which your encrypted packets do indeed get relayed through our root servers. Relaying through our root adds latency. The packets must travel farther physically than they would for a direct, peer to peer connection.
We do not throttle any of these packets, nor can we read the contents of the packets due to encryption. We also, however, cannot guarantee connection reliability when this happens. We do our best effort to get your packets where they need to go, but this is not always possible.
See https://zerotier.atlassian.net/wiki/spaces/SD/pages/6815768/Router+Configuration+Tips for more information on how to resolve such issues.