The machine was stuck on Ubuntu 20.04.6 LTS Linux 5.4.0-124-generic. It has been upgraded to Ubuntu 22.04.5 LTS Linux 5.15.0-170-generic. It was still too slow for normal operation after the upgrade. The provider scaled it up to compensate. Now it is working fine but a doubling in CPU and RAM seems quite strange of a need so sudden.
Yes, indeed both machines are hosted by the same provider. Regarding data center and node, I can not say for sure. Would a storage issue not reflect in I/O numbers of the VPS? Those seem fine.