Unable to archive IMAP email with GMail app

I'm using the Gmail app on a Pixel 2 running Android 10. I'm connecting to a private IMAP server (despite the app name, "Gmail" is a general-purpose mail client, not just for Google Mail). **How can I get it to recognize my Archive folder?** My IMAP server (Dovecot) offers an Archive folder, which is honored by all other IMAP clients (Roundcube, Windows 10 Mail). The Andoid Gmail app, however, does not show an archive button when reading the mail, and swiping will delete—rather than archive—the message. When I'm reading Google Mail, it works as expected; there's an archive button next to the trash, and swiping archives the message. With my Dovecot account, the archive button isn't shown, and swiping moves it to the Trash folder. Here's what the IMAP server returns for available folders: d list "" * * LIST (\HasNoChildren \Archive) "." Archive * LIST (\HasNoChildren \Sent) "." Sent * LIST (\HasNoChildren \Drafts) "." Drafts * LIST (\HasNoChildren \Junk) "." Junk * LIST (\HasNoChildren \Trash) "." Trash * LIST (\HasNoChildren) "." INBOX d OK List completed (0.001 + 0.000 secs). This is correct, and is honored by other clients. In the Gmail app, if I click on the hamburger menu when viewing a message, I can select "Move to", and it shows an Archive folder there (in fact, Archive is the only folder listed there). Selecting this does move it to the Archive folder. This is unworkable, though; I need the Archive button while reading, and I need swiping to archive instead of deleting.