Suppose some people are working on a contrib module (link) to provide obvious template suggestions that are not covered by default Twig template naming conventions. Display mode for fields, region for blocks, etc.
By habit I would use
hook_theme_suggestions_HOOK_alter. I simply add my suggestions following a certain logic, it's done.
This hook allows any module or theme to provide an alternative theme
suggestions of function name or pattern and reorganize or remove
suggestions provided by
hook_theme_suggestions_HOOK ()or sooner
invocations of this hook.
Then I see that there is
hook_theme_suggestions_HOOK which does more or less the same thing except for reorganize or to take off suggestions. But basically, looking at his description he does exactly what this contrib module is supposed to do.
This hook allows the modules to provide an alternative theme function or
model name suggestions.
And now I wonder which of these hooks should be used at best? Is it totally ours? Are there any disadvantages to using the
*_edit hook? Should we better use the simple suggestion
*_HOOK allow other modules to intervene later in the process?