Hey, the delegated EGLD from the web wallet doesn't appear in the app because Maiar doesn't have any delegation (legacy) section, it only has access to staking.
If you stake your tokens instead, you will see them in both apps. The delegation (legacy) will go away anyway.
And to use the same wallet, you can for example in Maiar say you already have an account, and input the 24 words secret key of your wallet there.
And vice versa, on the web wallet, you can also input the 24 words secret key and transfer there. Now you will have both accounts with the same private key (same account basica