In cases where 1Password won't autofill (for whatever reason), I wish there were a more convenient way to copy the username, password, then TOTP into an app.
This is the one feature that I miss from LastPass when I moved from it a couple years back: copy notifications for credentials.
Let me explain that, because I don't think that makes it very clear.
You select a 1Password entry, and there would be an option somewhere to show copy notifications for those credentials. You tap it, and a notification would appear for each piece of login information (username, password, TOTP; whatever the entry has) for the 1Password entry.
You then switch back to the app you want to fill. Tap the username notification and it copies the username to the clipboard, and you can paste it in. Then tap the password notification to copy that, then paste that in. The the same with TOTP. Then dismiss the notification(s) when you're done. Maybe they could expire and go away on their own after some period of time.