The new USB dock, currently only sold as part of the PinePhone Convergence package, has been estimated to be available for individual purpose by Q4 2020. It provides more ports useful to using the phone as a more traditional computer, including HDMI out USB-A, ethernet, and an additional USB-C to provide power.
Unless there's mechanical support, such as a docking stand, the cable is necessary as strain relief to avoid a broken USB connector. The linked item has a magnetic support to stick to the site of the iPad to provide this, but it's wider than the pinephone.
Yes, I see the problem. But the advantage is, that it is better for mobile use, where i need an additonal plug for a power bank. And the mechanical problem could be solved for instance by a strong glue tape.
I'm only using wifi, and I'm happy with it. But what I miss is a second usb connector for a power bank. I'm looking for a solution, where I can run the phone 24 *7 without going to sleep. A large power bank, which such a connector, one for charging and one for the power bank is the only solution I could find.
I bought such an adapter. I don't have a PinePhone anymore. I ve sold it. If got a Xiaomi Poco F1 now, but I suppose this phone has similar size than the PinePhone. The adapter is less than 1 cm broader than the Phone, and has the same thickness. When you stabilize it with a plate and same tape, I think it should work as a mobile extension adapter. You have then a mobile HDMI adapter, with an aditional usb-c and a USB 3, as well as an additional audio jack. This should work as a mobile Linux computing solution.