Mass Effect 3 DLC - XBox One issues...

My wife and I have wasted more than a few hours troubleshooting this. Yes, that means we've seen every thread out there and tried every common (and not so common) solution.

Here's our specific problem:

Launching from within the game (after going offline and back online to clear the "checking DLC" screen), all DLC we've purchased shows up as downloaded with check mark next to it, and we get 3 options:

Play now

Download again

Cancel

"Play now" is grey and can be selected but not clicked.

We've also tried launching from the Store, and while the base game shows "Installed" and "Play", all of the DLC only shows "Installed" with no option to play.

1) We have tried every possible combination of going offline and back online, to avoid the game hanging on the "Checking downloadable content" screen. This is a common problem with a common solution, and
it has worked every time, but as described above, we still can't access the DLC once we get to the title screen.

2) We've tried clearing all local saved game data. It has had no effect.

3) We have tried uninstalling and reinstalling the game and its DLC several times. We've also moved it all from an external drive to the internal drive, just in case that was the problem. No
effect.

4) We tried clearing the alternate MAC address, unplugging the power cable, waiting, restarting the console (as suggested by a Microsoft chat agent). Tried unplugging and replugging the router (it's a wireless
connection so there is no ethernet cable to unplug). No difference.

5) We have downloaded my wife's user profile to the console, which I think we had already done, but went ahead and did it again. Didn't matter.

6) We even tried installing one of the DLC's on our XBox 360. This required clearing a lot of space, since the smallest DLC is still almost 2gb and we had 330mb free on the hard drive. All that
time and effort and making room, downloaded the DLC, and encountered the same exact problem on the 360: Cannot launch from within the game ("Play now" is grey and not selectable). So, on BOTH CONSOLES,
(including the one the DLC was originally released for - so this is apparently not an XBox One problem??) we basically get the message, "Hey, we know you paid for this and downloaded this and installed it, but you can't play it!"

7) As a last possible resort, we actually went to the length of purchasing the base game we already own from the Microsoft Store, for an additional $20 (more wasted $!), just in case that was the
reason we couldn't access the DLC (we bought our disc copy of the 360 game used, so I dunno?). Of course this made absolutely no difference and was a waste of $20, but we were completely out of ideas.

Can anyone help?? Have any of you gone through the same painstaking hours of troubleshooting only to discover a solution that's never been shared anywhere on the internet??? We've thrown our hands up at this
point and accepted that we've wasted our time and money, but maybe there's still hope? This is by far the most ridiculous and frustrating experience we've had with DLC on any system.

Here's the only remotely helpful response we've received from Microsoft (even though it was something we'd already tried):

Sent: 2019-05-02 12:59:19 PM

Subject: (Mod Removed - Personal Information) - xbox support team

We are contacting you regarding you Mass Effect 3 DLCs launching issue, In order for you to be able to launch them, please clear the local saved games on your xbox, follow the steps below:

Please go to Settings ==> System ==> Storage ==> Clear local saved games.

Thank you,

Happy gaming,

Support Specialist

Xbox customer support

:)