Is there any documentation on how to change Substrate from PoA to PoS?
The following posts may help:
- How to upgrade consensus engine of a live chain from PoA to PoS?
- How to change consensus engine from PoA to PoS?
Also, you may want to consider the parachain route:
I have integrated the POS in fresh node-template on polkadot-v1.0.0
Here you can find the POS(proof-of-stake) node-template with babe: https://github.com/Aideepakchaudhary/POA-to-POS