@ZexMaxwell 

I'm familiar with what you are doing as I'm a Starlink Reddit user. (Got my Squishy on 20 Jan)...

First off...Just to cheer you up...Once you get your Starlink Ethernet Adapter you should not have an issue...I got mine two weeks after receiving the kit. I'm using an Asus Router (Merlin) and have about 30 1Gb Ethernet connected devices and everything is working great (Run my OpenVPN Client setup on the router as well)...

I had a ER 605 before the Asus router doing dual-wan switching but since then removed the ER605 as the Asus did dual-Wan Failover without a problem. I've since gotten rid of the backup provider and am single-stringing on Starlink now with the Asus router connected to the Starlink router via Starlink Ethernet Adapter (Starlink router In bypass mode)

I remember a similar issue to yours that others encountered in differing setups...They were able to resolve it by running the Ethernet Cable coming from the Dish into a switch and then to their WAN port of their router...Do you have a spare switch to try that? Not sure if it will work but if you have a spare switch you could try that. (If the switch has a DHCP server you could also try turning that on to get a different IP coming from the switch).

  @RacerX  I've tested a Dumb switch in between the Dishy(v3(Flat)) and the WAN port of the ER 605. I got the same results where the dish handed out a 192.168.100.1 and sat on it with no internet broadcasted. I dont have an extra Smart switch to test sadly.

Today, by some miracle, I got a internet connection with a proper IP. however, like clockwork, my internet connection ended at 10PM on the dishy and fell back on my backup. 

In the meantime while I wait for a responce from TP-Link support. I'm reading up about the Busybox system and how I could manually command the ER 605 to release and renew the DHCP address from starlink. I've seen there were ways to configure/update/script your way out of the issue. Just reading up on which way is the best and least likely way to do it without Bricking my device. Another work around is to get an IPv6 address, but so far from my setting changes, I haven't been lucky enough to get an address.

  @ZexMaxwell 

OK...Good luck on the scripting...As far as IPv6 on Starlink it was in a Beta testing state...Some had it working (I didn't bother as I don't need it)...But recently IPv6 on Starlink has not been working for people that previously had it working so that may have been put on hold by Starlink...

  @ZexMaxwell 

First, what is your network diagram? Are you running modem(router) to ER605? It's kinda strange to see that you get WAN IP dynamically and it's 192.168.100.1?

If that's a modem, have you tried to reboot that modem? As far as I know, the modem in the US would record the MAC address and only allows the device that is with the correct MAC to get Internet.

Have you tried the Get IP using Unicast DHCP under the WAN settings? 

BTW, are you using it in standalone or controller mode? 

Can you post a picture of your WAN settings? The current one.

 @John1234 

Here is the network map.

From my Google fu this is what I learned and why the ER605 needs an firmware update.

When the ER605 wants to connect to the internet via Dynamic IP. The Starlink DISH (modem?) Provides a short lease DHCP of 192.168.100.1 for about 5 seconds while acquiring satellites. Sometimes acquiring satellites takes longer than that, due to weather events. but the ER605 doesn't stay connected long enough since it's trying to look for an internet connection, so it disconnects. Normally, once the dish acquires a sufficient connection to the satellites and thus the Starlink ground terminal. The Terminal Sends a proper DHCP address back to the dish. The dish then passes this address along to normally their router but in my case, the ER605. but the Dish will still retain the 192.168.100.1 for statistical data for the Starlink app. The problem is, the ER605 still holds onto the 192.168.100.1 for dear life and doesn't obtain the proper internet IP.

Other Starlink power users say that their OpenWRT firmware doesn't have this problem. The assumption is, the firmware has the DHCP option 121 to hold classless IP addresses. Giving the router more IPs to check, I was hoping to stay with TP-Links firmware, but once the OpenWRT community started supporting the ER605. I'll probably switch over to their firmware. 

I've tried the Unicast DHCP settings and it does the same behavior. 
Currently using the Controller software from my PC to manage the ER605. Since it provides better management of the MTUs and bandwidth Up and Down speeds.