It can be trite to refer to "winners" and "losers" in a war or a battle, but I will still try to do so here.
Losers:
The Assad regime is clearly the biggest loser. I can't see a way for them back to Syria. Nuff said.
The Alawite population of Syria will likely face lots of resentment for the Assad regime's reign. They've also lost a heart-breaking proportion of their population. Their relative concentration in the coastal areas may help them against any backlash.
Iran lost an ally into which they had poured tremendous support. Syria offered a convenient, if contested, logistical hub against Israel. This is a major defeat for Iran.
Hezbollah, already reeling from the loss of Nasrallah and apparent military defeat in Southern Lebanon, is a clear loser. They do not publish casualty figures, but local estimates when I was in the region in 2015 were that as many Hezbollah fighters had been killed in Syria over two years as had been lost in all their battles against Israel since the 80s. The Syrian counter-insurgency campaign waged by Hezbollah was unpopular domestically, and was an awkward fit for a group that styles itself as a Resistance group. The rapid disintegration of the Assad regimen will certainly make people wonder why they invested so much blood and treasure propping them up. Welcome to the "foreign occupying armies that lost a COIN campaign club."
Russia. Their propagandists will try to spin this into something positive, but Russia definitely lost in Syria. They lost an ally, potentially lost an important logistical hub and their "stock" is now lower. They can recover and also mitigate some of the damage, bu they tried to prop up a regime and ultimately failed.
Winners:
Turkey has improved its position in the region and can influence the new leadership of Syria as it takes shape in a way that other world powers cannot.
Israel has seen an opponent regime fall and Iran/Hezbollah have seen their position weakened. There may be an opportunity to work with whatever government takes control of Syria to achieve some semblance of normalcy. On the other hand, this may be a devil you know vs the devil you don't know sort of deal. Still, I can't see any of the Sunni groups that have or will seize power being friends with Iran, so this will still likely be a net positive for Israel.
HTS. This group has had quite a month. Their future success will depend on their ability to find a path to legitimate governance that also satisfies their base. They've faced some internal criticism from hard-liners for softening some aspects of Sharia in their governance of Idlib. Their leader has shown remarkable pragmatism for someone who was a former member of AQ and a former cell-mate of the founder of ISIS. "There seems to be a gap in your resume?" In fairness, though, he has been saying the right things in terms of pragmatism. Or he could be the "tall poppy" in this phase of Syria's history and get snipped by others.
Uncertain.
The Kurds now have to face other opposition groups, most of whom who have the support of Turkey, without the common enemy of the Assad regime. They can't hope to take power in Syria, but perhaps they can obtain a separate peace that guarantees their freedoms? The US has been supporting the Kurds, but there is a Kurdish proverb that "They have no friends but the mountains." They've been abandoned before.
Rest of the World. The world is a better place without the Assad regime. It is hard to imagine their replacements being worse, and I certainly hope that nobody tries. There is still a ton of uncertainty, and this is therefore a dangerous time.