The perfect travel media streamer would (IMHO) have these characteristics:

• Powered (or power-able) by 12v DC or 5v USB or USB-C (even if it comes with an AC adapter, as long as it's capable of being powered by 12v DC from a car cigarette lighter adapter or from a standard USB-A 5v or from a USB-C it'll work for my needs - I don't mind MacGyvering something).
• Can run native client apps for Kodi, Plex, Netflix, Amazon Prime, Hulu, HBOMax, etc. (no casting from phone or computer required).
• HDMI output (bonus points if the device form factor is not like a FireStick or a Roku Stick with a rigid HDMI plug, because that puts it at risk of being snapped-off and broken in my car - but I'd just buy a short male-female cable to solve that).
• An included remote is good, but a remote with mini keyboard is better. If it has excess USB ports, I may use a mini keyboard + mouse combo .
• WiFi 2.4ghz and 5 ghz is the minimum, but on-board ethernet is better. In a pinch, I might use a USB-ethernet adapter or USB hub with ethernet and power pass-through.
• Ability to play locally stored files via USB (and bonus points if it is capable of significant internal storage, such as by installing an M.2 SSD). For USB playing, it should support all common file systems, including EX-FAT and NTFS, and video file formats.

My use cases are:

1. In the car (for the kids on long trips) . The car has a flip-down screen and HDMI input. There is a nearby USB-A 5v port to power this. There is a USB-C adapter in a cigarette lighter that could be used. There's an on-board inverter powering a 110v AC outlet, but it's not where I'd like to have something plugged-in all the time. Due to connectivity issues in the car, it will almost always be used to play local files, not stream
2. In a hotel room / airbnb / vrbo ... where it will be used to play local files, stream (Netflix, etc.) and use Plex to play files on my home Plex sever. For hotels, it will often need to be able to open a browser to get through the hotel's wifi login / acceptance-of-terms page - that is, unless I get a travel router.

I've looked at a lot of devices, but so far none tick every box - or they do so only with extra add-ons, such as powered USB hubs. I'd like to carry (and power) as few devices as possible - especially in the car.

This is a lot to ask, so I don't necessarily expect the total solution to be cheap.

The Nvidia Shield TV and Shield TV Pro seem like possibilities, but both require a 19v DC power source. To be clear, both come with a power adapter that can connect to any worldwide AC power input source from 100v to 240v, which it converts to 19v DC output. Most of the Intel NUCs also require 19v DC power. There are no good/elegant 12v to 19v car power converter/adapters on the market. At least not any that I can find. There are threads (e.g. this one ) where people have taken an Nvidia AC power adapter and MacGyvered it into something that worked off of a vehicle 12v system. I might have to resort to that.

The Shield TV / TV Pro, ONN media streamer, Tivo Streamer, Xiomi Mi Box S, Roku... all use external local storage. Only the NUC (or something like it) can install local internal storage so far as I can find. Being able to install a 2 or 4 TB M.2 SSD (versus connecting a USB flash drive or USB SSD) is attractive just for the sake of having fewer things to haul around.

FWIW... I will probably buy a travel router (e.g. something like the Gl-Net Beryl MT1300 ) just so that everyone and everything can just use the same SSID name and pw that we use at home.

Reddit Coins to the best two or three suggestions after a week.