Yes, Node.js v14 and SPFx v1.14 are compatible with each other.
Check detailed SPFx compatibility matrix at: SPFx development environment compatibility
Answer to your 2nd question:
Node.js v14 is the ...
Node.js version 16.x is not yet supported for SPFx development.
Node.js version to use is depend on the version of SPFx generator you are using.
For example: If you are using SPFx v1.14, you can use ...