Hello.
I've been playing Live for Speed for over a year now and I haven't had this issue until recently (about a week)

I'm able to play online for maybe 30 seconds before I start lagging, this happens on EVERY server, regardless of the location (including a server i hosted myself in the USA to test this), so I know this is not related location/ping.

I've been able to play on EVERY SINGLE SERVER just fine until recently, nothing involving my internet has changed at all, I get an average of ~140 ping in most servers which shouldn't be lagging me nearly as much as this.

I ran a network debug in-game (shift+F8) and the numbers it returns seems to go up ~100 each time it's printed into chat.

I've tried EVERYTHING to fix this, I've even went out and bought a new modem, still no luck.
I'm getting quite sick of everyone telling me my internet is slow, because it's clearly not.

What can I do to fix this problem? I just wasted $100 on a wheel which I'm now unable to use online due to this crap.

My modem's firewall is completely disabled, windows firewall is completely disabled, I have no anti-virus installed, and I turn off my VPN when I play live for speed.

As you can see, my internet much better than it needs to be to play this game.

Could it be that the RTC (realtime clock) on your machine is running faster/slower than realtime? If that is the case, I believe that you should get kicked out of the server if you wait long enough.

and how do I fix this?

I actually don't know the answer. I know that a person had that problem in this forum and Scawen diagnosed the cause of it, but I don't remember how it got solved.

More then likely a powerstate issue, try control panel > Power options > set to high performance. Can you post the spec of your PC?