Macbook Air 2019 will not boot from USB or complete Internet Recovery, Exhausted options

Call Apple or chat online with service would be my next step. Ask for a mail in repair if available and convenient. #3 is really unlikely to be anything easy if you have charged it for 2 to 4 hours.

Flat rate repairs for these are quite reasonable amd it would cover things like battery and or cpu board. Possibly under warranty or a program, worse case you get a quote for a professional battery repair.

A totally flat battery can drag the whole controller and board down. Hard to say until it’s in the shop with known good parts to test things out internally.

Ignore the answer you received above. Your Firmware is corrupted. You can easily fix this by doing DFU Mode

You will need another MacBook with a USB C Thunderbolt port. One is the host computer and the other is the Bricked computer (yours) you will have to restore it.

DFU mode will fix this computer issue IN Most cases. once you restore it from DFU, you will now be able to use internet recovery properly. BE WARNED though, your SSD will be wiped, and if you do not know your iCloud password you will not be able to restore your device (if it is locked to an icloud account).

Hope this helps!

YouTube Video to help you do it step by step https://www.youtube.com/watch?v=UaVgBP4gJsU

Also failed to mention: your MacBook Air 2019 has a two USB C ports. The port closest to the trackpad has to be used for DFU mode or it wont work.