There are actually many power banks/chargers of good quality on Temu.
Some of the listings are blowing smoke, but reading reviews and the product description associated should clear up any doubt.
Just be careful of impossible claims (100w charging, done in 15 minutes, etc).
One thing to consider is the way in which you'd use it. Sometimes it's better to have 2 10ah (10,000mah) rather than one 20ah.
It's kind of a trade-off between storage space, power needed, and speed desired.
There aren't many products that I'm aware of that risk battery damage, but the weight of the charger, heat output, and strength of magnet are all things to consider.
I've gotten several different sizes, capacity, and rates of output. The few issues I've experienced are: slow charge time for the charger itself, weak magnetic attachment, excessive heat output, and odd physical dimensions/inaccurate dimensions given.
All in all, it's pretty easy and safe to find one (or multiple) to meet your needs without high cost or risk involved.
Definitely pay attention to your battery protection settings in all cases
