With a soldering iron and USB-CD PD trigger boards, I've successfully converted a few of this kind of thing.

There are barrel jack USB-C adaptors now that you can just glue in place. Very useful for homelabbers.

I love them, useful for super clean desk setups .

I use a 140w USBC charger -> USBC to Barrel Jack -> LG Ergo screen -> USBC -> Laptop. One AC plug powers the display & laptop.

The step I've taken is just purchasing USB-C to barrel in various voltages and labeling them appropriately.

I think that's changing too, my son got some cheap radio controlled boat a few weeks ago, the remote uses AA and the boat has USB-C as input (interestingly enough, it has a weird USB-C cable with a built in light to signal when charging is done).

I recently bought a very cheap RC car for my kids, and it was USB-C rechargeable but instead of having a port it just has a USB-C cable that comes out of it and plugs into a power brick. I love that.

Wait till you enter the world of more advanced RC stuff, that's when the Cambrian explosion of connector types really happens.