First ever digitals! complete beginner, taking them alone. Any advice before agency submissions?

Hi! I'm a 20 year old male in UK, and I've been trying to take my first ever digitals before agency applications.

I've 0 experience in modelling nor in photography, so I hope my really improvised background setup is excusable. I've also been taking these photos with a timer or by exporting frames on a 4K video, using the rear camera of a mobile phone.

I'm struggling a little with taking full-body photos because I'm finding it difficult to find somewhere that I can fit where the background is not too cluttered, and I don't need to stand too far away from the camera, so I've had to switch out the background, although I hope it's still passable.

I'd really appreciate any advice on the lighting, framing, expression/posing and really anything else I should change! A few of the agencies I've looked at say they don't require professional photos so I also wonder if I've been really overthinking it. Thanks!!!

PS - some measurements for context:

• Height 186cm/6'1"
• Chest 90cm/35.4 in
• Waist 70cm/28 in
• Hips/Seat 94cm/37 in