iPad Mail - search and bulk delete?

how can I search for all email containing a specific phrase and then bulk delete them?

let’s say I have an Icloud inbox with 2000 emails and 1700 of them have a subject line with the phrase XYZZY in them. I would like to bulk delete all of those emails. From my iPad I can search and find the emails. Then I can click EDIT. I would like to do a SELECT ALL to select them all and then hit TRASH. But all I can seem to do is to manually select them one at a time and them hit TRASH which is very painful.

if I do NOT do a search then, when I click EDIT there is a SELECT ALL button available. But I don’t seem to have that option after search. Is there something I am missing?

thanks in advance!

PS I am running the latest version of iPadOS - 13.7