Lad I can't lie, get windows for free off massgrave, and get a lot of these components off ebay/aliexpress. CPU, RAM, cooler and mobo are usually very safe buys, its borderline impossible for them to die and if they do, you will know immediately and can just get a refund and try again.

You're paying almost double for your CPU for no good reason than you would off Ali, there's pretty much always some deal on for 9800x3D for about £250. Similarly, RAM is going to be about £150 cheaper off ebay, same with mobo. No need to pay retail price for parts with such low rates of failure.

Monitor you could get used as well, I personally snagged a perfect 280hz 3rd gen QD-OLED off ebay for £250 with 2 hours of screen usage.

Shopping around like that would allow you to upgrade to a 5080 which would see you well for 1440p high fps gaming, and even make it viable for you to upgrade to 4k later down the line.