From my understanding it varies from airline to airline.
I’m looking at the Air Canada page that has details for example which can be found here.
But I’m not sure certain what it means.
Can I have a portable power bank that’s 160W? If I bring that could I also bring on a laptop and a Steam Deck?
It seems like you can bring 15 devices theoretically.
I generally brought my Switch, my laptop, and a fairly beefy battery bank, and of course my phone. Never had problems; take them out at the baggage scanner and put them in the tray, mostly because they block the scanner’s view