Hey PH, I've been working on cascade.page as a way to easily create, view, and edit timelines based on a simple markdown-like text file. I even used it successfully this past weekend for coordinating and sharing a timeline of events surrounding my own wedding!
It supports locations, images, links, multiple pages, dark mode, ISO dates, casual dates (like June 4, 2021, or Dec 12 9am), and more.
I hope you find it useful, if you have comments or feedback I'd be happy to hear it. Also feel free to open issues on github!
Markwhen