Hello,
On the Yahoo!Mail android app, please give your Yahoo customers the ability to search within a folder. I have already been in touch with Customer Support. I have very easily replicated the issue and provided screenshots, and they confirmed customers cannot use this feature as its not available on the product.

On the mail app, I'm inside a folder and I use a keyword search, but the Yahoo results return every occurrence of the search regardless of which folder it appears. In Yahoo!Mail folders, where there are hundreds of emails filed, your customers should be able to easily search within a folder like you can on Gmail, iCloud, Proton Mail, etc.

Thank you.