Hi 19y...
TiddlyMap and Stroll are not rivals.
Stroll and TiddlyMap are two different kinds of animals. Stroll is not a
plugin but is something like an edition. TiddlyMap, on the other hand,
is a plugin, so it can be added to any TiddlyWiki file that doesn't have
other pieces that conflict with it (as Stroll seems to do). I imagine
there are many here using TiddlyMap but just don't mention it. It's a
great tool and it is nice to have mind maps in TW.
We did try to integrate TiddlyMap into Stroll, in part because that imitates a feature of Roam Research, which was what we were shooting for, and in part because people were asking for it. But it was hard to do because of the two story rivers, etc. TiddlyMap needs room to breathe in the sidebar, and Stroll was squishing it, and I think there was some other issue, but I forget.
There is a tool called TiddlyRoam, which is basically just TiddlyBlink (a precursor to Stroll) with TiddlyMap added onto it. That is probably what you want.
Drift is similar to Stroll and has some extra features, such as taking tags more into account. I imagine TiddlyMap could be integrated into it.
With my Customizer plugin, it would be possible to create a TiddlyMap-only sidebar, which might make it more prominent. But I haven't had the time or energy to create one myself.
I hope the above helps to give a little context and history. Blessings!