I am putting together a mobile looping rig with my BOSS RC-505 so I can loop while walking.
I currently have a chest desk and portable power bank.

I need advice on what I should look for in a portable speaker. I would prefer something with a 1/4 inch input as that is the BOSS RC-505's main output. Would you recommend I look into a portable guitar amplifier, pa system or a single speaker? Another option would be a higher end Bluetooth speaker or "party box" with an auxiliary input. However this way I would have to use an adapter and I'm worried that would cause a loss of quality or latency. Looking for something I could realistically carry on my back via a backpacking frame. Ideally it would have a good bass/low-end but I know that can be somewhat unrealistic with the size/power output I'm looking for.

I currently can loop with headphones on the go with no problem but I'd love to be able to perform to the public.
Any advice would be greatly appreciated.

Additional details:

-The portable power bank has a voltage of 120 and a 42000 milliampere hour
Battery capacity. I am willing to upgrade this if necessary.

-The will be attached to a backpacking frame.

-I am using a dynamic microphone to loop with this setup but plan on adding a keyboard or synth on my arm in the future.

tl;dr: building a rig to use a loop pedal while walking, what kind of mobile speaker should I get?