up grade a sondors thin

I have sondors thin , I would like to up grade , what is a good hub motor and battery to up grade too. ?

What are you trying to accomplish? You can get more range with a larger capacity battery. You can get more speed by using a higher voltage battery, and more torque (acceleration or hill climbing) by using a controller that provides more current (amperes).

You don't need to change the motor unless you increase the power so much that the original motor overheats.

To be honest, the Sondors needs bike component upgrades at least as much as it needs electrical component upgrades. Tires first, then front wheel, rear rim, and brakes. Cable discs are fine, but not lowest-bidder cable discs.

it all depends what you need ebike for!
couple of times a/summer on one end OR commuting 5 days/week spring, summer, fall say 7months in a year.
Sondors is good for occasional use , definitely NOT for heavy 250 days/year use.
in such use all would fall apart pretty fast, cheap components first.
As Chialo said very well start by replacing all major components.
why to cheat yourself - you get what you pay for rule applies to BSO more than to any other merchendise.