I think it would work for forces to take Sukhnah (and Taybah, Kawm, and Kadir), have some dig in, have a vanguard unit or two go north and connect with forces from Ithraya at Khirbet Bir al-Qusayr, and have troops from Hama and Homs push east while these connecting forces push west. With heavy artillery barrages, RUAF air support and SyAAF bombing from Tiyas, that pocket should be finished off soon. Forces from Qaryatayn can simultaneously move toward Khunayfis and the nearby mines to prevent any counter-attacking ISIL forces. Forces from Suweida can push forth and sandwich the pocket between ISIL and the rebels down there, while Aleppo forces can push east to Maskanah as the Iranians hold off Jabhat al-Nusra and the gang in the plains.

After this massive operation, a good chunk of Syria is secured. Special forces from the Palmyra-Sukhnah area can securely extend a line to Deir Ezzor while the SDF pushes toward the river from the north. Forces from East Aleppo can push toward Deir Hafir and Tabqa, taking two airbases in the process. This can occur while the SDF takes Manbij. With Deir liberated, the SAA there can push down and secure the area, and send their best units to begin the crushing of the Aleppo jihadists with superior artillery, RUAF and SyAAF bombing, rocket barrages, Iranian and Russian missiles, as well as Iranian, Iraqi, Afghan, Pakistani, Lebanese and Syrian forces. This will be the mother of all battles. Once Jabhat al-Nusra is finished in the north, the rebels of the north will fold as they will be helpless. This will free up Iranian forces who can be transported east to chase ISIL to Al-Bukamal, while the ISF and PMU's can move west to pressure ISIL, and the KRG and ISF can all this while (from the attacks I've described up top to now) attack Mosul to divert as much ISIL forces as possible, ensuring swift victories in Syria.

With most of ISIL wiped away, the RUAF, Coalition, and Iranian Air Forces can fix themselves on al-Raqqah while the SAA and SDF do a joint sandwich attack on the city after laying siege. Down south, freed SAA and Hezbollah can take the Tanf border area and clear the pockets near Damascus. A deal can be reached with the Southern Front whereby the SAA and militias take on the ISIL pocket, without involvement of Hezbollah and the Iranians and with extensive RUAF support.

Remaining forces can be used to clear up pockets, and total victory is won with West, South and Central Syria going to the government, while North and East Syria (along with the border to Turkey) go to the SDF. Negotiations can begin then over governance and inclusion. Meanwhile, Iraq will be divided between the KRG and the Iraqi government.