forget about any other solution. The only way to fix the wireless upload speed issue is to use your ax86 in AP mode.
Most fios/fiber with symmetrical high speed connections straight from the otn to asus ax routers will not give you the full wireless upload speed apart from ax89 and I am saying this from multiple installations I did.
It was brought up to asus support attention multiple times from different customers they will start by asking you to do what
@L&LD asking you to do, hopefully you give up and if you don’t and nothing changes they will issue you RMA claiming its defective then replace it with a refurbished one.