Replace obs4 with a better pluggable transport
There have been papers attacking obfs4 and similar pluggable transports such as https://ieeexplore.ieee.org/document/8855280.
The obfs4 maintainer (Yawning) also has said that the protocol is outdated and unmaintained which is not a good thing for something that is the primary pluggable transport for the Tor Browser.
The Tor Project should initiate an effort to create a better, secure, more resistant and more up to date pluggable transport to replace obfs4.