The concept totally works but I would worry about using a beelink in a business context where I had to support it.

For up to low hundreds of users I think you're better off just with 1 vertically scalable box for all the officey / web server workloads.

You mitigate the hardware failure stuff with a vendor contract where you can get someone on-site and overnight you parts, and by keeping things super boring. Volume replication is not boring, avoid at all costs. NAS or SAN if you have to but all disks in the main box for as long as you can.

For 20 person SME maybe a 2-bay Synology or similar, for a heavier company a low end 2U with hardware support. Proxmox under the OS for reduced worry snapshots, rollback, backup etc. Proxmox is there for operational flexibility, resist the temptation to create a network of VMs, you just need 1 CT or VM with all the workload inside it.

For container workloads on 1 host Portainer works as well as k8s IMHO, it gives you the key property you want - you can IaC everything declaratively with terraform + compose over an API.

Caveat that if CI gets heavy you might need to scale that out but you can keep it stateless.