Changing Page Navigation

I’ve been using old versions of WordPress for a long time. I’ve made many changes to the scripts in the themes I used as a basis. I’ve made many weblogs, one for each of several vacations we’ve taken.

Now I am trying a different approach. I’m trying to have ONE “weblog” for multiple trips, and doing the whole thing with Pages. I’m trying to have a front page which shows Trips, and for each trip, an Itinerary page, which shows places, and a text page which contains paragraphs and media for the entire trip. The entries on the Trips page link to Itinerary pages, and each entry on an Itinerary page will link to an anchor somewhere on the text page.

The world has changed. Using the default Twenty Twenty-Five theme, I think I’ve figured out how to do everything except one thing: I don’t want Page Navigation which shows all the pages (since there will be more and more pages as time goes on). I’d be happy for that area to show just the Parent page (ie nothing on the Trips page, “Trips” on each Itinerary page, and “Itinerary” on each text page. That is, I’d be happy to have a block I can just set the name and link of.

But in this modern world, all I get to do is to try to figure out how to do things with Blocks, Patterns, Templates, etc. There’s no code to inspect or modify, at least not viewable from the admin UI.

I’m guessing I’ll have to make my own page template, and I’m not even sure how to go about copying an existing template to modify (I did find out how to create a new “empty” template). It’d be interesting if “Parent Page” were a block type, but I don’t see it.

I suppose one possible solution is to make a template without that bar at the top, and to include my version of it as Content.

Does anybody have any suggestions how I should proceed to change this one element?

The page I need help with: [log in to see the link]