I've never heard of the brand and always heard to get Anker or Ravpower. Is Tecknet still reputable? Is there anyway using this or any other charger can damage my internal batteries (extra worried because I just got this MacBook and don't want to destroy the battery).

I have this - with all 3 poirts I can simultaenously charge my M1 MBP, iphone + any other device. Just be aware of the output of each port and what combinations it allows.