Is there a difference between a wall wart for charging and one for power?
I have an LED light that came with no power supply, only a USB-A connection for power. I had it connected to a wall wart, then this morning i noticed it was noticably dimmer than usual. So i plugged it into my Anker charger and it was bright again.
So i am looking for another wall wart, but is one that is a charger fine? Or do I need to seek out one for power?
A lot of those USB powered lights actually need 5v 2A chargers, which many older adapters aren't capable of or could barely manage. So the light may work, but may be dimmer or end up slowly killing the adapter by trying to pull more power than it can really provide.
A good quality 5v 2A or higher adapter, like Anker, UGREEN, etc. is usually all you really need, not necessarily anything fancy with USB-PD support or multiple voltages.
Led lights need constant current with a limit on the max output power. Chargers output a constant voltage. Too high of a voltage can be damaging to leds and if they get too much current they burn out quickly. So there is a difference between for example a phone charger and a proper led power supply. Also modern phone chargers communicate with the phone to deliver the right amount of power and often will fall back to a very low amount when a "dumb" device is connected.
That said, the led light might have a power supply or power converter builtin. In that case you can supply just about anything with enough power into the input and it will be fine.
If the light wasn't expensive and a random charger works, just connect a random charger. It probably isn't worth looking for the perfect power supply.