Some articles about refugees returning to Syria and who is even interested in that or rebuilding Syria.
https://www.reuters.com/article/us-mideast-crisis-russia-syr...
https://www.wsj.com/articles/russia-seeks-u-s-help-in-return...
https://www.irishtimes.com/news/world/middle-east/return-of-...
The article [1] estimates the number of members of anti-governments on order of tens or hundreds thousands people. You cannot just hire 100 000 people out of nowhere and send then to Syria. Most of them are local people.
the russian invasion of ukraine was an attempt to salvage a geopolitical rout in which the US politically captured ukraine, an area under russia's dominion for roughly a hundred years.
the attempted salvaging has mostly failed; an overtly anti-kremlin government sits in ukraine.
importantly, they have retained the strategically critical hinge point of crimea (militarily one of the doors to control of eurasia), which was the most valuable piece of ground at risk in the entire debacle, independent of the political aspect. note that their access to crimea is now much weaker than it was before because of how close it is to a US-orbit government.
you will notice the difference in importance of the objective by seeing how they did not leave the invasion of crimea up to their proxy/"rebel" forces, which are currently in eastern ukraine. indeed, as soon as it was at risk of being out of their hands, the russian marines were in crimea in force, with only a minimal denial of the effort. the justification for it was invented later.
they were scrambling, and the rough edges of their plan were heavily showing.
the russians are not wantonly destructive. the refugees are indeed helpful for their global position, and they do want to prevent the middle east from entering the western orbit -- you will recall that the US has been cozying up to russia's major client state in the area, iran.
but they don't want chaos. they would prefer it if there were no chaos, at this point. chaos costs them money, increases the chances of them not being able to react to another crisis, and damages the stability of their client states. furthermore, trouble in the middle east ends up coming home to russia fairly frequently thanks to their longstanding conflict with the sunni muslims.
Surely all those countries were just one step from becoming best uncle Sam's friends before Russia came. Right.
The Russian invasion of Ukraine should be counted as a success for Russia, rather than a failure; they wanted a buffer zone and have got it. They're operating under the logic that every inch they destroy is an inch the "West" has lost, the same logic that led to Napoleon's defeat.
Same goes for Syria. The goal is to keep the fire burning and refugees fleeing, to prevent the Middle East from stablising in a West-friendly state. Keeping Assad in power is beneficial but not critical to the overall pro-chaos project.