So if I can't boot into the OS how is one supposed to turn off Activation Lock?

Rethinkmedia wrote:

My internet is very slow and intermittent and so that could be the problem.

So I'm looking for a way to access the installationOS on the usb and do a fresh install from there. I'd prefer not to have to access the internet for any part of this installation if possible due to the issues above.

So you have successfully painted yourself into a corner with your stipulations.

To access "installationOS" to create a USBinstaller requires Internet access as well...

If this is a notebook it is easy enough to try a different Network: ex, sit outside a Starbucks, Laundry mat, McDonalds, Public Library— all tend to offer high Speed wireless Internet.

If you have another Mac that is functioning on your Network:

How to create a bootable installer for macOS - Apple Support

Unfortunately it is slow and dodgy Internet/download speed that tends to corrupt/interrupt a viable install package.

Rethinkmedia wrote:

• I'm trying to recover the MacBook Air, I'm trying to install OS Catalina from a USB thumb drive.

The Mac can't boot normally.

• It can't boot into OS recovery Mode, 'Command+R'

• The Mac can't recover from the internet recovery screen, just shows a -1008F error after 10mins

Is there a ways to hardware force the mac into recovery mode so I can install from a USB?

If your Mac starts up to error -1008F

https://support.apple.com/en-us/HT206989

Your Network is inadequate in some fashion.. try a faster Networks and see if it is a simple resolve.

-1008F error...

In Internet Recovery, these low negative thousands error messages indicate that your provided Wi-Fi Network is inadequate in some fashion, and cannot be used (for this purpose) in its current state.

Common problems include:

Hidden Network-name

required use of a proxy server to get Internet access

required use of a login page to get Internet access

Use of a login server or certificate to get Internet access

Use of PPPoE in the Mac to get Internet access (typically only applies to DSL)

Use of Fixed IP address rather than good old DHCP

Variance of the time by more than five minutes

Failure of Router to provide workable DNS server addresses, or providing 0.0.0.0 [may produce -2002f]

If you have an Ethernet port, you may in some cases be able to move your Mac close to the Router and connect to the Router using Ethernet.

The higher the number, the more obscure the problem.

Also, make certain the Date&Time and Time Zone are correct within 5 minutes.

ref: Grant Bennet-Alder

https://discussions.apple.com/thread/250370425?answerId=250705456022#250705456022

Power Cycle your router

Disable any VPN or Proxy server

Uninstall any third party Cleaners,Optimizers,Anti-virus

Do a safe boot  https://support.apple.com/en-us/HT201262----

Did you already create a bootable USB installer?

If so, plug it directly into your Mac and hold the Option key down when starting. You should be given an option to boot from the Install macOS whatever USB Drive.