The rebels are backed by Turkey (proxy ground) and the US (air/intelligence/special operations). Assad is backed by Russia and Iran.
When Russia attacked Ukraine, they had to pull out of Syria. Iran took control of influencing Assad. Then Hamas attacked Israel, so Iran had to take an eye off of Syria. At the same time, without Syria Iran can't buffer Israel via Hezbollah.
Assad's backers are weak, and the rebel's are on the move.