Hey, please add a possibility to change default action from delete to archive. This is the main reason why I can't use Thunderbird for Android as default mail client
If your looking to change the default action when swiping left/right on an email, this can be achieved from the general settings > interactions > swipe action menu.
If your idea is regarding the options presented on email notifications, a community member has recently submitted a pull request to add this feature. You can follow the change and see if gets merged into a future app version.