It is difficult to make simple mapping between Roam, Obsidian and Tinderbox as whilst all use notes, they so differently. Experience of one may be unhelpful as a start point for the others.
Roam and Obsidian are both powerful but are so by finessing only some features found in Tinderbox. Roam’s block level linking is sort-of there in Tinderbox (see my previous) post. Obsidian majors on simple Markdown-based text and its link graph. Tinderbox supports use of Markdown but it is not a default (the app long pre-date’s Markdown’s invention). The Tinderbox hyperbolic view offers a link-based diagram of the document.
By comparison, Tinderbox offers a wider set of tools but without the narrow feature optimisations—which is why better/worse comparisons don’t aid understanding. Some key things to explore are the multiple (concurrent) views of the same underlying data and strong support for incremental formalisation. Tinderbox’s inheritance and prototypes are both powerful affordances.
Probably the biggest difference coming, as you say from Roam/Obsidian, is that whilst you can just as easily type in your notes and connect them in Tinderbox, it offers a larger toolset to allow you to explore your understanding of your data, rather than your data having to fit into a app design optimised (with good intent) for a particular focus on how the data should fit together. Thus, inevitably there is ‘some assembly required’ to get the best out of the app, compared to process-optimised apps. But, if you don’t start from the premise of looking for the ‘correct’ (i.e. app dev’s view) method of how to use the app you should find it easy to get into. also, experiment with features in small text docs; this lessens confusions due to false negative/positive outcomes and keeps your real docs freer of cruft. It is not difficult to split documents if needed. Indeed, Tinderbox is very forgiving of false starts.
One doc or many? My suggestion would be to start with one and see how scale works. There’s no one-size-notion-fits-all here. You might have multiple docs split by topic but not time. You might have all topics in one time-frame. The sweet spot will come from seeing how your own natural way of thinking is best reflected (note: your thinking as opposed to “computers says”).
HTH and do ask if stuck on anything.