Eight signs you should upgrade the VPS
Swap, load average, RDP lag, and queue depths. The plan names are not a loyalty ladder.
Upgrade when the guest is honestly out of resources: sustained RAM use with swap, load average above CPU count, disk wait, RDP that stutters while the network is fine, CI jobs that time out, or a Minecraft TPS you cannot fix with view distance.
Do not upgrade because a landing page said "enterprise." Herald is enough for a quiet reverse proxy. Sovereign is not a personality.
Use the client area upgrade path or a ticket. Back up first if the resize is not in-place.