Hargeisa is the second largest city in SomaliWeyne so it’s logical for various reasons which you stated but it boils down to do Somaliland accept that which they won’t nor will the FMS accept it either.Hargeisa makes more sense as the capital of Somalia for its proximity to the Gulf of Aden. Most regional players beyond Ethiopia are located in that direction. Mogadishu is a little too far removed. It can still be a major commercial and military hub. The move might as well patch up regional relationships within Somalia.
Look at Istanbul. It used to be the capital of the Ottoman Empire. The Turks have moved their capital to Ankara. Istanbul is still the biggest city in Turkey and a de facto commercial and financial center of their country.
If Hargeisa is such a no no for the Federal member states, we might look into setting up a brand new capital city at the northeastern tip of Somalia close to Ufeyn.
I personally think the Capital should stay in Mogadishu as it’s less hassle. If it was moved it could cause violent protests and up roars etc