Because the 14" only needs a 96w charger for fast charging which under the 100w limit of the portsRecently found this old thread. I'm using an ISDT 200X 4 ports charger with apple USBC to magsafe cable that reaching 140W charging speed on my 16" M1 Max mbp
ISDT Power 200X USB-C Charger Max 140W (2 Type-C 240W Cable Included)
ISDT Power 200X USB-C Charger Max 140W (2 Type-C 240W Cable Included)www.amazon.ca
but when using usbc to usbc, I can only achieve 90W because apple's limit.
Fast charge your MacBook Air or MacBook Pro - Apple Support
You can fast charge your MacBook Air introduced in 2022 or later and 14- and 16-inch MacBook Pro models introduced in 2021 or later up to 50 percent battery in around 30 minutes. Learn which power adapters, cables, and displays can fast charge your Mac.support.apple.com
No idea why 16" mbp can't while 14" can.
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