Comment by scosman

I saw you may rename your project. IANAL, but don't do that. They might have invalidated a European registered trademark, but you have first use and continuous worldwide use which means a lot. Not all trademarks need to be registered. Again, IANAL, but I can't imagine they can harass you with their mark. They just formally made the case that your usage wasn't in the relevant market, and in the case of the US mark, that their usage is somehow substantially different from yours. This will make it nearly impossible for them to now argue your usage is competitive/conflicting. Them taking action would likely have some risk for them; their lawyers would likely advise against it. They probably won't do anything now that they have what they wanted.

More generally: don't treat the lack of registered mark as something you need to act on. You were doing your thing just fine without a registered trademark in the other ~180 countries. Just keep doing what you're doing.

Fighting it will be painful, expensive, stressful and unrewarding. But that doesn't mean you need to go change your name.