Online gaming drops constantly starting 3 months ago

I wouldn’t use gateway’s WiFi for anything other than casual use. 

I'm impressed you’ve hung onto the 2Wire as long as you did.  

Have you tried the suggestion I made about putting your router into AP mode?

It’s difficult to say if the stats are an issue.  Doesn’t look to be so.  

I might try a test session with the console Ethernet connected to the gateway to see if the game behaves differently.  

You could try running ESO with the PS5 connected directly to the gateway via Ethernet to see if you can reproduce the problem. 

Unfortunately that won't work with  our setup, as the ATT modem is in an upstairs office room with no TV and the PS5 is downstairs in the living room. I will say that our kid's Minecraft online games never drop, and she plays that while on Zoom with a friend at the same time. We've never had an issue with those, so perhaps ESO is more sensitive to technical issues.

Someone on an ESO forum did suggest extending the length of time before the dynamic IP changes (or if possible, get a static IP). Apparently since the latest update a few months back, there have been reports that it is more sensitive to this, though have not seen anyone reporting it on this level. 

Also, could this simply be the modem hardware getting old? I remember setting up our bridge to the Linksys router was a bit of a pain, that was the only reason why I've been dragging my feet on getting a new modem but ATT customer service has told me we can get one sent out any time.

Modems get old, yes, but they don't suffer from progressive degradation.  The hardware we have is very reliable.

Att internet, while not advertised as a static IP, is static for all intents and purposes.  Easy to check. 

ESO is nothing special.  Start with the premise Att internet is working correctly.  You'd need do the work to isolate your home network from the gateway to ensure a service test is 100%. There are broadband statistics that can be examined as well.

And because you haven't offered any details on your home network about how it's configured, the issue can be there.  BTDT. 

Fair warning. WiFi in Att gateways is marginal. 

Any advice on how to troubleshoot the home network? The setup is:

ISP > ATT 2Wire Gateway 

ATT 2Wire Gateway > Linksys AC3000 via ethernet (ATT 2Wire's wifi is disabled to avoid device confusion; we got the Linksys to provide stronger and more stable wifi)

I used this stability test to provide the data above:

https://test.vsee.com/network/index.html

Happy to provide further info, please let me know what might be helpful. 

Update to this -- I activated the 2Wire's wifi and we connected the PS5 to it to see if it would be any different than the Linksys. I ran the stability test to gauge any difference in quality/packet loss/jitter and delay. So the weird thing was that ESO actually stayed connected for 3 hours with no issue. However, the quality of data speed and issues was actually slightly worse with the 2Wire wifi. This was why we bridged it to the Linksys in the first place a few years ago.

So in summary:

2Wire: Stats show less quality connectivity BUT it stays connected

Linksys: Better quality connectivity but sudden regular drops

Does this seem to indicate failing hardware with the Linksys?

2Wire is the original brand of gateway for the old Uverse product, circa 2010.  3800 and 3801 were two I’ve had.   Is that what you have there?   Att will probably send you something newer but interestingly for your setup, nothing really noticeable in terms of improvement.  A BGW210 is a likely choice unless you have Uverse TV with coax, but even that gateway is 6 years old already.  

If you haven’t done so, set your personal router to operate in Access Point mode.  Otherwise you’ll have to make changes in the gateway.  Everything else should be okay.   If it’s practical to do so, connect the console using Ethernet cable.  

Since you’re able to get into the gateway, check the broadband tab to see if any excessive errors are being logged.  I’m guessing it’s fine since you don’t seem to have any other issues.  

It's the 2WIRE 3801. I've just ordered a new one from their customer service. Are the new ones known to have any better wi-fi coverage? That was the reason we got the Linksys in the first place, there were dead spots in our house when it was just the 2Wire and then I discovered that ATT's native modems didn't have great signal.

A full day has gone with the Playstation connected to the 2Wire wifi -- there's been more moments of noticable lag. So that all checks out, whatever is going on with the Linksys seems to be intermittently causing drop errors but stronger signal when it actually connects.

I checked the current Broadband error log, this is the only line item to have anything. Does it appear to be related to my issue?

It looks like it was already in AP mode (I remembered jumping through some config hoops years ago and it matched this). Looks like this is all that can be achieved via ATT, so now I'm moving onto a Linksys forum to see if they have troubleshooting suggestions for my router. Hopefully I won't have to buy a new one. Thanks!