Thunderbolt 3 hub with Thunderbolt 2 port?

[trueislander]

I may not fully understand the TB3 spec and it's backwards compatibility so please feel free to scream "Not possible!"
I only have a single TB3/charging port and would like to find an adapter/dock that offers a TB3 as well as TB2 port. This way I can still charge my notebook while using my TB2 external drive. Any ideas? I've already searched here and r/apple as well as r/hardware and haven't found anything but dongles that only go TB3 -> TB2 or a dock that adds more TB3 ports, which would still require a TB3 -> TB2 dongle