Looking at the docs there's a lot of things that are in tech preview state
- BTRFS
- OCI
- Snapshots as volume chains
- Import Wizard
- IPAM
- FRRouting
- Nftables
- static-load and dynamic-load scheduler modes
- CRS Load Balancer
I have never heard or seen a date for graduating these out of that state but yes, it's still tech preview according to the docs.