I'm not sure what exactly a travel-related hobby app might even be for (other than e.g. a map and a calendar, but there are FOSS ones), but isn't this exactly demonstrating the "creator" mentality? You can make your blog as you like it with text, images, videos, etc. Share it with people in your social circle who are interested. Maybe others will find it too some day if you want it to be open. But if you can't send them a link, they're not really your peer, are they? And if they won't click a link, they weren't interested.

Let me give you long-haul bicycle travel as an example: back when there was an active blogging scene, people sharing route tips and bike-build breakdowns could be sure that a decent amount of other people would find it and benefit from it: the blogs got picked up by search engines and were readily findable, and there was still a culture of using the open web.

Today, no one you will see the content that you posted to help other people out. Google began deprioritizing personal blogs a decade ago already, and now a whole generation has come up that doesn't know the open web is a thing. When people look for tips in this hobby, it is overwhelmingly on phone apps like Komoot or PolarSteps, on the general image-based social media like YouTube or Instagram, or (already for an older-skewing crowd that still uses browsers) on the big for-profit website Bikepacking.com that grew by using its SEO-fu to wipe out the non-profit-driven scene.

There is a community around this hobby, one with a lot of IRL interaction, and people do enjoy that feeling of community. But claiming that people "aren't really your peer" if they don't use the old open web that we knew, is just cutting yourself off from that.