Hi there, I was going to post this on your crosspost on [email protected] which is where I saw this first. I see that you're more of an end user rather than someone uploading this info, but I'm gonna dump my spiel regardless I'm afraid:

If you are going to put this info somewhere I would suggest you dump the info on OpenStreetMap. The information you put onto OSM will get used EVERYWHERE else- komoot, alltrails, Osmand, Organic Maps, you name it. And the license is permissive so everyone else can use it. All Trails (to take an example) is all very well and good but all the nice pics, all the info, all your time and energy gets put into their nice little closed website which they then use to make THEIR website better and nobody else's!

So at the very least, put the info you collect into OpenStreetMap first, and then elsewhere. There is a lot more info you can put into OSM than you may think at first glance. Width of trails, Trail difficulty, trail visibility, etc etc. All this gets put into tags. (even trail dangers if I remember correctly) This info then will improve the hiking experience for everyone using a mapping application around where you have mapped. (Everyone of course, except for people using google maps or apple maps, yuk!)

Now this extra bit is tailored more towards your original question, as an end user. The closest thing I can think of is https://hiking.waymarkedtrails.org/ as someone else put in here. The info, of course, comes from OSM. If the trail you are looking for isn't marked there, you can put it into OSM and it will eventually make it onto that website. (As well as Osmand, and Organic Maps, and Komoot, and... you get me)