This is like asking parents to choose their favorite child!
Choosing a platform to buy Jackbox Games on depends on a lot of things. Keep in mind that games are not transferable between platforms, so if you buy on one and decide you want it on another, you will need to make another purchase, so this is an important decision!
One very popular use case is bringing a laptop with the games to a friends house which can combine the power of a console with the portability of a set-top box or console. If that's the case Steam(PC/Mac), Epic Games Store(PC/Mac), or the Mac App Store is the way to go since you can bring these with you anywhere or install the game onto a computer that's already at the destination via the relevant software and potentially playing via HDMI on a TV where everyone can see it. Nintendo Switch and set-top boxes like Amazon Fire TV or Apple TV are also very portable.
More powerful platforms like Xbox One and PlayStation run the games really well, and the Xbox One X and PlayStation Pro render some of the games in 4k which is very pretty. Note however that these are less meant for moving around frequently.
Ultimately, the decision is up to you!