Be advised, that a bunch of the High Level garrisons have Tarantul Corvettes/Frigates, its pretty much a corvette/light frigate with 2 Strategic Missiles strapped onto the side, additionally Tactical Groups on Hard like to have these tag along with them.
Working in Strike Groups is probably the best way to go, as if a ship gets significantly damaged the entirety of your strength won’t be down while you are Repairing, and you can cover more ground, and delete more enemies for the same amount of Fuel Expended.
When making your own design, I recommend a single Cruiser-Sized ship to bring in with the Sevestapol and then with whatever funds you have left a Fuel Tanker, and then have the additional Cruiser+Tanker as one group and the Sevestapol as the other.
I recommend that as soon as possible you replace 1/2-2/3ds of the Sevestapol’s 57mms with 37mms, since the 37mms provide real proper anti-missile Defense while you should still have 57mms to demolish Frigates and Corvettes properly.
Kindness does nothing, so go ahead and ignore Survivors, the additional modules you’ll have the spare time for will either be used to repair your ships or can be used to cover the costs of fuel or repairs.
Also, you want to go Hunting for the Strategic Groups, you REALLY want to yeet them before you get to Khiva.