I have bought TESSAN products for this purpose (convert 3 prong to 2 prong) and given that my laptops can be powered by either the power adapter or USB-C, I also got a minix adapter. Both have worked very well for me when I am in Japan and elsewhere. One thing to note on power, Japan is rated at 100V which is lower than the US 120 so some devices might take longer to charge than you expect. Also, it means that you need to ensure any electronics you buy can manage the higher voltage. This is generally not a problem, most items come with adapters, but not all, and there were a number of items that I did not bring back with me from Japan for this reason.
I used to carry a complicated and heavy device to convert power to US standards. Then i read the small print on my power supplies, and every one of them is rated 100-240 volts, 50-60Hz. So now i just carry plug adapters.
Yes that is generally the way to go, for me though, in particular the minix adapter, I like it because of its size and the multiplicity of outputs so I can use it for more than one device at the time. I bought it both for the plugs and the portability, which is why I still use it as my main power adapter.
The Anker power supply I bought has 2 USB-C outputs and one USB-A output, and you can use all three. And it’s small.
But i confess, in Europe, my US - EU adapters effectively remove the ground, too. And any old US power supply that isn’t grounded, or with an adapter to get around that, will work fine.
Yeah, if you shop around a bit you should be able to find a 10-GB eSIM for maybe $25. As long as you’re not watching movies with it, that should be plenty to get you through two weeks.
If your home e-SIM is still on board, you should be able to set it up so that the Japan eSIM is used for data, and your home e-SIM is used for WiFi-based calls so you can make/receive Canadian domestic calls while you’re in Japan.
In general, nowadays there are only two types of electric devices that need voltage converters: Devices that produce heat, and devices that have motors. But of course always check the specs on your devices.