I personally have a Digitakt, but that’s twice the OP’s budget. The Liven Lo-fi, on the other hand, ticks all the boxes:
Under €300
Hardware
Samples and resamples
Effects
Amenable to long pads/drones (not [only] percussion-oriented)
Check out this short ambient video of someone using only a couple of found sounds in their kitchen, I really dig the underlying melody:
sounds so warm 
And looks easy to use, maybe you found my next instrument …
Not that it’s a competition or anything but I did post that exact video in this thread a week ago 
Sorry about that! I somehow missed it, even though I did read this thread through. I do remember someone else mentioning the Liven series early on but came across this video yesterday and thought “wow, this sounds just like what OP is looking for” so I posted from phone.
No no worries at all, there’s been an overwhelming number of suggestions that it’s easy to miss stuff and it’s worth reposting some of these. I just thought it was amusing as it was something that came to mind when I first came across the thread 
Still playing around with samples, got a nice setup now on a Midi Fighter Twister for all the controls I need. Got some nice lo-fi crackle stuff from a binaural recording I did outside when it was raining on my coat hood, it’s going through some FX including the wonderful TAL DAC -
The tone in there that you can hear was just some distant engine or something, when the sample is pitched up like this it becomes a part of the instrument. Part of why samples are so great for textural stuff like this.
1010Music Nanobox Lemondrop is a great little ambient machine. Just outside budget unfortunately but, ticks a few boxes otherwise
This is new
the Sonicware LIVEN Lofi-12 seems to be a pretty choice. i agree you’re opinion about lyra-8, its a very special one. i think with only granular synthesis character you will not be happy too. regarding the examples from burial and fever ray, sampler, just tones or seq. looping, from some kind of synth + delay/reverb and little bit layering should bring you to this sounds and sometimes u need nothing more than a short choir sample from freesound.org for example + muuuch fx. 
this tool is so dope !
Absolutely. I’m a patron of RemixSample, and he’s still making beautiful ambience with his old Volca Sample, and more recently, also with Koala Sampler. Give him a basic device, and he’ll create the ambience.
This guy, RemixSample, and his Koala Sample Packs, which I access thanks to being a patron of his on Patreon, has singularly been such an inspiration to me on how I can use Koala in an ambient process. He’s really open to conversation about how he puts his sounds together, and to answer questions from patrons. I recommend him highly.
In a similar vein, Krischer: