The UBOS way of doing things is generally not to edit config files. We are trying to make it so that the user should not even have to know that there are config files. This has many advantages, including that site maintenance over the long term (including backup, restore, host migration etc) doesn't accumulate a lot of cruft.
The right way for us to support what you want to do is to add some customizationpoints to the nextcloud-auto-mail-accounts accessory (to use UBOS terminology), which then are used to automate editing whatever config files need editing. We do this, for example, for the Nextcloud/Redis integration. Here are the relevant files: https://github.com/uboslinux/ubos-nextc ... ache-redis
We don't do that yet for auto-mail-accounts -- for one, I'm not aware that it has many users and nobody so far has asked for that. If you think this is important, could you please log an issue here: https://github.com/uboslinux/ubos-nextcloud/issues/new
. You are also welcome, of course, to clone the repo, and make the changes yourself. Pull requests appreciated