Great idea for the "name unavailable" problem: Optional Title-prefixes

Everyone would have their normal names. This pool of names is drying up.

GGG would implement prettified 'titles' to display in towns, etc.

Defaults:
If you choose to have a title, it would default to fx Sir/Miss.

Further unlocks:
Rest are unlocked from certain game milestones, like boss content.

Step 3:
???

Profit:
This would obviously give WoW-title vibes and would naturally lead to people actively looking for those that have the less common titles - a shift from the current system where players mostly ignore each other in town.
More eyes on MTX -> More money for GGG.