How about some software for server management and app hosting like cloudron.io ? It is a complete and easy solution to host your own (docker based) apps or you can just install free apps from the build in app store. You can use Cloudrons base image to make use of addons (services) that are already build into Cloudron like: graphite, mailserver, mongodb, mysql, nginx, postgresql, sftp, turn, redis, ldap, oidc, recvmail, scheduler (cron), sendmail and tls or build an app on top of the LAMP app.
Everything is automated from OS updates, plattform + app based backups (with persistence if needed) to proxy setup and certificates. Besides the webUI, Cloudron also provides a RESTful API to manage apps, users, groups, domains and other resources. It also has its own Build Service and Image Registry or you could host your own Gitlab/Gitea with just one click.
Instead of real orchestration you maybe could use automation tools like n8n or Ctfreak to archive what you need.
Cloudron is free for up to 2 apps so keep that in mind but it runs well on a VPS with as low as 2GB RAM and 25GB of disk space.
Okay lets say you go the prosumer approach:
1x QNAP QuTS hero TS-h973AX-32G ~ 1300€ each
2x Samsung OEM Datacenter SSD PM9A3 15.36TB, U.2 ~ 1400€ each
3x Toshiba Cloud-Scale Capacity MG10ACA 20TB, SATA 6Gb/s ~ 300€ each
Right at 5k and you get 15TB NVME RAID1 (mirror) and 40TB HDD RAID5 (parity). Without mirror/parity it is 30TB NVME and 60TB HDD raw space.