Any USB-C Power delivery charger with >24W (I think 27W is the next existing level) should be fine. Make sure it is a reputable brand such as Anker, Aukey, Ugreen, Baseus, Sharge, or any of the big phone/notebook brands such as Samsung, Xiaomi, Huawei to avoid a fire hazard.
A quick Amazon.com search led me to this which can deliver 30W per type-c port which should be plenty. 8$ seems like a really good deal.
https://www.amazon.com/UGREEN-Charger-Charging-Compatible-Macbook/dp/B0DG93MZCR
EDIT: Damn it, BLF did it again and showed me the start post as if it were written today when in reality only the latest reply was new…
Regarding those yellow things: Do not use them (or any similarly unbranded crap) under any circumstances. They are incredibly bad engineering, and apart from not meeting anything near their specs they are a big fire and electrocution risk. How they can be sold on Amazon is beyond me, people selling this shit should be imprisoned. I design high power electronics for a living, and after seeing a teardown of one of these I would not touch it with a 10ft pole.