If you can find something not made by Microsoft, go for it, but I actually picked up a surface go 3 and installed fedora on it. As long as you install the Linux surface kernel it's actually a really good experience. The only thing that doesn't completely work are the cameras, but there are workarounds (and anything using libcamera works).

You might be able to find a discounted ThinkPad X12 detachable with an i5. It does not officially support Linux, but most features work, except for the volume rocker. It's become my daily driver -- really won me over. The keyboard is great btw.

I'm really tempted to order a StarLite, and I feel like that would be the best fit for you, but understand the hesitance to be an early adopter. Maybe you can pick up a used device to tick the boxes and order one later.

I think most folks touched on the main ones as well as what you posted. The Librem 11 could potentially be something else to look at, but not sure about the German layout and price is above budget. Theoretically you could also look at doing a Steam Deck with a bluetooth keyboard, although the screen may be a bit on the small side, but would be well within budget even with buying a separate keyboard.

Personally I haven’t had much experience with Linux based tablets. I would say the guy who mentioned converting the surface 3 to a Linux tablet would probably be the best bet for the set of requirements you’re looking at

I use a Lenovo IdeaPad FLEX 14API with PopOS on it, it's a flip over style covertible with stylus support and it's working pretty well for me. The specific model I have is a few years old now, but there are certainly modern equivalents. The only hardware on it that doesn't work out of the box with Linux is the fingerprint reader, but I don't use that anyway.

The Starlite certainly looks like it would fit the best for you, but like you said, it hasn’t shipped yet.

I use a Lenovo IdeaPad flex 5 14" running Manjaro as my daily driver. Tablet with stylus works fine, and the fingerprint reader even works using some 3rs-party library for libfprintd. Only issue I have is sleep doesn't always work, (though that's a pretty standard problem for most Linux laptops) and I could never get it to rotate into portrait mode successfully (I tried tools to manually change the screen orientation but that makes the digitizer not line up properly with the new orientation.

Another small note is that the built in keyboard started failing on me, and it's very difficult to replace, so I have to use an external keyboard now. This may be something you have to deal with but it didn't seem to be a common issue online.

Arch wiki link: https://wiki.archlinux.org/title/Lenovo_IdeaPad_Flex_5_14ARE05

I picked up a used HP Envy x360 with the ryzen processor and it's been pretty good. The stylus is t a full digitizer like a Wacom, but it's good enough for sketching

My daughter had exactly the same situation (just without serious coding) only few years ago. Her result was a Samsung Tab S6 lite. Their proprietary note taking app was the best with the stylus.

Surface devices: seem to work pretty well, although I would prefer not to support Microsoft

I was suggesting you would get one of those second hand. There are good deals and they indeed work and are light. Personally I would love to see Linux on the iPad but that's not going to happen. But we've to admit, that would've been the perfect Linux tablet because it is very light.

Asus flow z13 works with Manjaro and arch according to Reddit. I have one, but haven't had time to replace windows yet.

I just discover https://puri.sm/products/librem-11/ and it looks great !

Not sure if it feat every point, specially the german keyboard ?!

As someone with an SP8 running Garuda, I would really recommend going with an Android tablet l with a keyboard ike a Lenovo P11 rather than a Linux device for your use case. The truth is that x86 devices just aren't that great when it comes to power management, Linux is hit and miss when it comes to suspend functionality, and the stylus / handwriting implementation is typically pretty poor. You can make it work, but you'll be compromising a lot of functionally.