I am afraid it is not easily possible without additional extenstions that are available on the markeplace and be able to lock the attachement from editing.
If you choose to edit you download a copy and then you upload it as a new version.
Maybe you can have some info on a page (for example a task macro) where the attachment is located that someone is editing currently and ask to uncheck the box when work is done? Thanks to that at least you would have a process to prevent editing on the same time and be able to know who is actually doing that (and contact that person)
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