2017 Legacy aftermarket head unit.

[miller17legacy]

Trying to replace the head unit in my 2017 Subaru Legacy. I have the 6.2 inch screen non hk system. Can anyone link me the proper wiring harness, steering wheel controls and backup camera retention interfaces? I’ve bought 2 adapters now that do not work. Trying to install an Alpine ILX-W650. Kinda wondering if I should just keep the stock and run an lc2i but even with new speakers installed the sound quality is pretty bad.