Google sheet Query formula that use text from one column to match another column returning text from-CodePudding

I have a dropdown text column, Claims!B2:B that is supposed to match Ref!A2:A and select Ref!B2:B text.

I tried

=ArrayFormula(IF($B$2:$B="","", LOOKUP($B$2:$B,Ref!$A$2:$A,Ref!$B$2:$B)))

some results not consistent

=QUERY(Ref!A2:B,"Select B where A = "&B2:B&"")

resulting in error

=FILTER(Ref!B2:B,Ref!$A$2:$A=B2:B)

wrong results and not arrayed.

I like to know what should be the simplest array formula for the scenario and if possible correct my other trials for my learning process.

Sample data attached.

Functions used: