Best/Most Direct way to get from Karlovy Vary to Olomouc using public transportation as a Senior

Train. About 6 hours with a train change in Prague
https://www.cd.cz/en/

train is probably the best option as buses just too complicated, there are a few options with a least one change in Prague and others with 2 or 3 changes. You can get around 50% discount if over 65 but if you decide to go First class then there is no discount.