So if you’re on Centos I presume you’re using bash or something else that use export to set environment variables? If not an option is to try sticking the environment vars directly as java arguments like @mesquest and I worked on in Jar file migration H2 to MySQL in Windows?
Can you post the log output from your console? It should contain info on Metabase using MySQL not H2 as application database
What MySQL version are you using?