The only advantage for stranded wire is that it is more resistant to damage from frequent flexing. Solid wire is generally cheaper, and entirely satisfactory for your purpose.
I recall once talking to a store clerk about solid vs. stranded wire of the same gauge. He said stranded wire was better because electricity travels on the surface of the wire, and stranded wire has lots more surface area. That's total BS !!!
Actually it's partially true. But not in this case. It's the omissions of details that were left out. Higher frequency current does travel on the surface of the wire. It's called skin effect.
In the case of ordinary stranded wire, the surface area does not increase much since the wires are all shorted together. Stranded Litz wire does have a reduced resistance to higher frequency ac current because all the strands are insulated from each other.
Another sales pitch I heard once was that connectors were gold plated because gold is the best conductor of electricity. Not true. Gold is inferior to copper and copper is inferior to silver. Gold plating is used because it does not corrode. And the plating is only a few atoms thick so not much resistance is added to the connector pins with the gold plating.