I highly recommend PC. Over the last couple decades they have gotten vastly more user-friendly. I have multiple nephews and nieces who won't touch consoles anymore once they started using Steam, the best PC games storefront. "Big Picture Mode" on Steam looks just like a console user interface and is designed to be controller-friendly. Good for kids.
The problem with consoles is that while they're cheaper and easier to use at first, they cost you so much more down the road. You get locked into a console's crappy ecosystem and pay higher prices for the games with nonguaranteed backwards compatibility going forwards.
And nowadays on console they don't even allow most third party peripherals anymore. When your kids break that $90 controller that's going to get old fast.
Microsoft releases all of their games on pc now. And Sony has been releasing most of the games on pc after a couple years. PC also has tons of its own exclusives. And there are constant sales and bargain prices. There are multiple storefronts where you can hunt for deals.
You can upgrade your system down the road so that it's always able to play the newest games. Installing extra storage space or a better graphics card is super easy.
And honestly using a PC is a great way for kids to learn about them. An alarming number of children today have no idea how to use a computer or how the file system and components work.
There are some downsides to PCs of course. Occasionally there will be problems with a particular game and you'll need to Google search a fix. Or check the Steam forums (the community us very helpful). But this is usually pretty simple, and usually happens with older games. There is also a higher upfront cost. Although this is heavily off set by the cheaper long-term upgradability, backwards compatibility, cheaper peripherals, and cheaper games. It's worth it to just bite the bullet and get a decent system. Something with an AMD Am5 CPU socket for potential future upgradeability.
I've been a pc gamer for 20 years and I would never go back. Also have an Xbox One X. I use it once in a while for a couple specific games or to use the blue-ray player. But it's honestly very frustrating and slow to use after pc.