As we see there are 2 meanings of “so-called” that can be confused or misinterpreted, of which one implies falsehood and the other doesn’t.
One. to show that something or someone is commonly designated by the name or term specified.
“Western Countries belonging to the so-called Paris club”
Two. used to express one’s view that such a name or term is inappropriate.
“she could trust him more than any of her so-called friends”
Since so-called I feel is very often used to suggest that a title for something describes a meaning that isn’t necessarily accurate, what’s another term that simply expresses that something is titled something without judgment of the title?
“what is (generally/widely/typically/often) known as” comes to mind. Any variation of that would do the job.
It can also work not to use any term, but rather to introduce the name without fanfare. This implies a neutrality of judgment. “Western countries belonging to the ‘Paris Club’.” Even in speech one can often hear the introduction of a term by subtle changes in tone of voice.