I own a domain registrar.

Personally (not our official position), I would never try to bring a trademark into this type of dispute. Once you make a trademark claim the domain gets locked to prevent any further changes and you get directed to file a UDRP. We will then act based on the ruling, which could take months.

Same for trying to send "intimidating lawyer letters" (or having your attorney contact us at all). Outside of a few narrow cases, nothing obligates us to spend money on legal resources to respond. But once you demand specific treatment under the law, we have to direct you to a court holding jurisdiction over us to rule in your favor.