Personal modem & Comcast modem, router won't get internet when modem is in Bridge mode

My personal Nighthawk CM1200 had been working for a couple of years at my old house (different ISP). I recently moved to Florida, and the modem activated on Comcast and worked for about 6 months. About 6 weeks ago Comcast notified me of some infrastructure updates in my area to prepare for multi-gig service offerings at some point in the future (my service still is, and was 1 gb). The morning of the upgrade in my neighborhood, I was using my network up to the min that they cut service. For me, the service never came back when they texted that the work was complete. I have had many techs out to look at this problem, here is what we know:

The Pole to my house wires were replaced out of precaution. The signal was slightly high, so they added a splitter to knock it down a couple of db which got me inside the range I needed to be in. What we figured out on the first tech visit was my Router would get internet through my personal CM1200 modem anymore (yes we rebooted everything in a variety of combinations). I could connect a PC directly to my modem and have internet. So they now blamed my Router that worked before the update. So I grabbed a spare common Linksys consumer router, which also would not get internet through my personal modem. But I still had internet when the PC is directly connected to the modem.

This is when I went out and bought a brand-new modem. Had another tech come out to the house. We activated the new modem and rebooted it all the ways that the tech in my house asked me to. I still get the same result! Both routers can't get internet through this new modem, but a PC directly connected to my new Modem gets internet. In that same Tech visit, we then activated Comcast XB8 modem. It worked at first, but I get the same issue after we enabled Bridge Mode. Once Bridge Mode was enabled on the Comcast modem, the router can't get internet. But a PC directly connected to the modem gets internet. So 3 techs, 3 modems (one is Comcast) and 2 routers, all doing the same thing. This is when that tech "had me speak to his boss to get an engineering case going". I found out days later that there was no case started and nobody can see any comments about it in my account. Not impressed, hoping we can do better on this forum.

I started up my Starlink system with Bridge Mode on that modem, and my existing Router works as it always did. Starlink is expensive and not ideal, but this should prove it's not the network. Something between Bridge Mode and the Comcast internet side is causing my Cisco Router to say this:

2024-04-17T13:51:01-04:00 <error>asdclient: Last message ' ASD Client failed t' repeated 5 times
2024-04-17T13:46:01-04:00 <error>asdclient: ASD Client failed to get access token.
2024-04-17T13:36:49-04:00 <notice>system: device booted with active firmware version: X.X.XX.XX       <----masked detail for privacy
2024-04-17T13:36:47-04:00 <notice>system: argument:all
2024-04-17T13:36:47-04:00 <notice>system: ##Checking lanwancheck work around Here
2024-04-17T13:35:47-04:00 <notice>system: argument:
2024-04-17T13:35:45-04:00 <notice>system: #Checking lanwancheck work around Here
2024-04-17T13:35:03-04:00 <notice>netifd: Interface 'wan1' has link connectivity               <-----WAN 1 was the only internet connection at this time
2024-04-17T13:35:02-04:00 <notice>netifd: Interface 'wan2' has link connectivity loss
2024-04-17T13:35:01-04:00 <notice>netifd: Interface 'wan1' has link connectivity loss
2024-04-17T13:35:00-04:00 <notice>netifd: Interface 'wan2' has link connectivity 
2024-04-17T13:35:00-04:00 <notice>netifd: Interface 'wan1' has link connectivity 

Now, you might be thinking the easy way out "don't enable bridge mode". That is how I have been working for a few weeks, for now. But the issue is that I now have a network behind a network "Double NAT" situation where I can no longer reach my media PC remotely. The "Double NAT" is the Comcast modem (NOT in Bridge Mode) acting as one network, then my Home Network is behind that.

I understand IP reservations and Port forwarding. With some time invested, I can make Plex work, but I can't select a custom port number anymore (not ideal to have a known popular port open). But "Roon ARC" won't connect, served from the same PC that Plex runs on (all worked for over a year before this issue). I have spent a ton of time on this, we are 6 weeks out from issue start. the 4/17/24 date seen in the logs is the date on my third Comcast service appointment, the one where his boss was "opening an engineering case".

The reason for this post here is that these applications have worked without issue on Comcast, in this house, and the same network on my Netgear Nighthawk CM1200 modem for 6 months. This was before the Comcast multi gig upgrades to my area. If I understand it right, personal modems run in a "Bridge Mode" type of way.  If I could use Bridge Mode even with the Comcast XB8 modem, this wouldn't even be a post. The issue is I need to remove one of these NATs to get back to normal, and I am not removing my personal network. I'd love to solve the root issue and get back to normal use. I get that this is advanced, can you help?