Current problem
If and when the first forum msg or attachment is deleted, it is unable to be re-entered again. Which means if the creator wants to reupload or change the first forum attachment, it is impossible.
Proposed change
A workaround could be to allow for image links to be posted, such that when editing the first msg, all we need to do is also edit the image link to change the forum header attachment.
Alternatively something more “professional” could be to have a setting in the forum channel like server avatars, where you can upload or remove the forum headed attachment at anytime.
The same should be done for the 1st forum msg which shows up in the header beneath the forum title. This could work similarly with how text channels have a description box that allows for the channel descriptions to be editable and removable at any time.
Platform
Windows, Web, iOS
Additional information
Discord has the option of editing image links in the 1st forum msg to change forum header attachments.