There are some additional features in FSD (non beta version) but that stack has been around since 2016ish IIRC. When you subscribe you get the same FSD that folks who purchased outright get.
Now FSD beta is an opt in. Once you request it should update on the next check for updates provided you aren't on a newer software version than FSD build.
Lastly, FSD beta has been halted due to the NHTSA recall meaning they aren't letting any additional users opt in. The current speculation is that FSD 11.3 (not yet widely released at time of writing) will address all the issues in the NHTSA recall and they will open it up again to new users. Have to wait and see on this.
My current recommendation is folks that want auto lane change and navigate on autopilot features just purchase EAP. It's $6,000 and includes a lot of FSD features.