About your sd2 issue, it looks like you don't have enough VRAM available, or at least the driver is not able to allocate any more? In which case there's no way it will work with Flux, which takes a lot more VRAM.

You could try running sd2 with --type q4_0 and see if it works (it will take a long time to load)

--type q4_0 just made my PC just almost OOM, GNOME force killed off things including terminal to save it, this is depressing honestly, as for FLUX1, willing to try if it magically works, can I get any VAE and use it for it?

You need to use Flux VAE, which can be found on Huggingface pretty easily. I think SD3's vae might technically work with Flux, but the output will look completely broken.

--type q4_0 just made my PC just almost OOM, GNOME force killed off things including terminal to save it, this is depressing honestly, as for FLUX1, willing to try if it magically works, can I get any VAE and use it for it?

Better only specify type when converting model files, otherwise it needs to convert it in memory everytime.

@LePichu can you grab the sd_turbo-f16-q8_0.gguf from https://huggingface.co/Green-Sky/SD-Turbo-GGUF and post a log with minimal command line parameters? (also use model specific params mentioned in the readme)