If you want to get an idea of how far you can go with live looping, this is one of my favorite videos (Rico Loop wandering around Berlin with looper, a mic and not a whole lot more).
Here's some riffing I did on the Stairway to Heaven solo that showcases it: https://freerobby.wistia.com/medias/vcajgqerla
If it appears "dead", that's mostly because it's essentially finished. It has all the features you've mentioned above, and then a whole lot more. All open-source and GPL'ed. Also fully controllable from e.g. MIDI pedal boards or OSC applications.
I like working within Ableton for a few recording workflow-related reasons but agree SL is fantastic as a standalone tool.
https://www.youtube.com/watch?v=v9GyoUmhKU0&ab_channel=Casey...