Are you asking about the current (outdated) 2.0 module or the 3.0 module that is still being developed? In 2.0, once you enter FIPS mode you cannot leave it. In 3.0 you can switch among FIPS and non-FIPS as you need to. See https://www.openssl.org/docs/OpenSSL300Design.html for a description of 3.0
FIPS ciphers are a subset of the ciphers that OpenSSL supports.
