I've decided to abandon the plan to just hide in the cave for a few years and write next version of Misago from scratch. I've got quite a lot done, but to build it all it would take me years of having to split my attention between 0.x line and future line.
Luckily in the meantime the world has caught up and Django naw supports enough of asynchronous Python and the ASGI protocol that makes it possible to port over a hefty amount of work that was done for v4.
My current plan is to complete the work on improvements for 0.x line: update the posting UI, add in-app notifications, advanced search screen + few other small tweaks and changes. After this work is done, I will release Misago 1.0.
After Misago 1.0 is complete, I will focus on porting the improvements and changes from Misago v4 back to current version. Top priority for me is to simplify user permissions because its source of major pain when working with features.
After user permissions and groups my next focus would be updating Misago's HTTP stack to make it work with ASGI. This will let me start working on GraphQL API for future client.