Dell XPS laptops (and some others) can also warn if the charger isn't providing the full wattage the laptop is rated for. This warning is an option that can be turned off in the BIOS settings.
I usually turn it off because I sometimes intentionally do day trips with a smaller/lighter portable charger which delivers 45w to my laptop which can need up to 65w due to having a discrete GPU. However, 45w is more than sufficient to charge the laptop during normal use on the Balanced power plan with iGPU. I only need more than 45w when gaming with the discrete GPU active.
Weirdest part was it was 100% charged, so could have booted with 0 Watts of charger but decided not to boot with 20 Watts more.
If I have a lower wattage charger connected on booth it shows me that information but I can just press enter to continue. It's just a warning.
Maybe it's a bios setting?
Workaround is of course to boot without a charger connected and then connect it later :)
Sure, you or I would just unplug the charger and run on battery but bad UX decisions like that generate a support call to me from my 95 yr old mom. It should not only warn and continue to boot, it should use whatever power is on offer to reduce the rate of battery drain.
Since a >$1,000 automated lab cable throughput tester is overkill, my thumbnail test for high-speed USB-C data cables is to run a disk speed benchmark to a very fast, well-characterized external NVMe enclosure with a known-fast NVMe drive. I know what the throughput should be based on prior tests with an $80 active 1M Thunderbolt cable made for high-end USB-C docks and confirmed by online benchmark reviews from credible sources.