ds room was planned when he was around 7 so there was as much practical storage with easy access to keep it as clear as possible and it has grown with him and hasn't changed (other than new age appropriate paint colours/pictures/new mattresses) for 10+ years:
Faux black leather ottoman bed/headboard (double if you have the space) - loads of storage for a bean bag, spare duvets, spare bedding, pillows, inflatable mattresses, sleeping bags etc for when he had sleepovers.
A set of IKEA Malm low/wide 2 x 3 drawers - 5 large drawers for clothes, 1 for his small bits of junk. This gave a low top he could put things on to keep them off the floor, and eventually he had a TV wall mounted above it with his playstation, clock on it, he keeps things like his laptop, phone charging etc on it when not in use etc.
He has a small fitted wardrobe - which hides a lot - dookets for toys, games, books etc. The short hanging rail isn't used except for school uniform. His clothes are mostly casual so go in drawers, anything occasional smart can hang in my wardrobe.
He still has the old glider chair from his nursery for clean/worn once clothes, a slim Laundry basket and a small bin keeps the room tidyish. He has a long window sill and a radiator cover which provides ledges that he can use to put things (originally dinosaurs, piggy bank etc and now teen things) on to keep them from accumulating on the floor. Just a blackout blind and no curtains to keep it neat. There is also 5 hooks on the back of the bedroom door for dressing gown/bulky hoodies.
A wall mounted light above his bed for reading is also useful and tidier/takes up less space than a lamp.
Shoes/jackets are kept downstairs. He normally uses either my WFH desk in converted garage/utility for homework (since lockdown we have squeezed another desk into my bedroom which he uses for remote schooling). If you have the space, it has worked well for him to have a separate quiet space where he gets into study mode/can keep his school books tidy without the distractions in his bedroom and keeps his bedroom schoolwork free for relaxing. Now he is older and has lots of school notes/books we have a slim IKEA billy bookcase with extra shelves added so he has a separate shelf for every subject and it keeps everything tidy.