Installing smart switches in 2-gang box with switch loop
Can’t do it.
There’s a “Great Wall of China” between the left switch (and its cables) and the right switch.  You cannot cross that with any wire, except safety ground.
It’s a Code violation, it’s a safety hazard to workmen working on the left circuit... and what’s more, if there are any GFCIs or AFCIs in either circuit, it will trip them.
What you might be able to do is reverse flow.
Depending on load factors, you might be able to flipper-oonie (that’s a technical term) the right-side lamp circuit so it isn’t powered at the lamp anymore.  Cap off that supply at the lamp.  Then flip this former “switch loop” so it is not a switch loop and powers the light in the normal way.
By “load factors” I mean you’re now throwing all of that light’s current onto the left circuit.  If it’s a large light, that could be a provisioning issue.