Ill be spending about £4000 in a desktop (not trying to show off just to put into context), I after quality but not things overpriced, I after a wearable mic and directional for build guide or projects, good 4k cam with god fps and no juddering nice and smooth, im thinking about £300-400 for a cam, and max £100 for two mics
Journalism student here. I specialize in written content, but I have filmed my fair share of items, too. Not gonna lie, I'm not an amazing videographer whatsoever, but I think I might be able to help you at least a little bit. Honestly, the image quality you're gonna get depends more on your skill as a videographer than the camera you use. You could have an Arri Alexa, but if you don't know how to use it, it's gonna look like a first gen iPhone. I'd continue using what you have, and work on your skills that way.
If you're adamant about getting a new camera, 4K at that budget is really pushing it, especially considering the fact that you're gonna need a lens, too. You might be able to find a used Panasonic G7 at that price, but don't count on it. 4k 60fps is completely out of the question at £400, too. Most camera's that offer that go for well over £1k. And when you're just starting out, you shouldn't spend that amount of money on a camera.
I do second a decent DSLR, like an older Canon. Maybe look at the Sony A6000, too. 1080p60, decent image quality (really good if you learn how to colour grade), and great for stills, too.
As for microphones, you're gonna struggle to find a camera at that price point which takes two microphones (DSLR's don't really offer that). So if you want to use two mics, you're probably gonna need a separate recorder (think Zoom H1).
Another good option would be to use a Rode Videomicro on top of your camera, and then buy a Rode Smartlav+. The Smartlav works with your mobile phone, so you could record audio through that and then sync it in post. It's not as hard as it sounds - clap your hands a few times loudly before you start recording, and use the waveforms to line the audio tracks up.
But like I said, I would probably use what you have now to improve. Learn how to properly compose a shot, and experiment with different camera angles. Learn how to use natural light to your advantage. Just keep trying, the nice gear will come. I've subbed to you too, can't wait to see you grow!