MacBook Pro (15 inch 2017) Extended display does not work if laptop closed after Ventura 13.7.4 installed

Have a MacBook Pro 15" and have had two monitors attached for years. One is an Acer, and the other a Dell S2421HN. I keep the laptop closed and use the monitors as extended displays all the time (the Acer is probably set as the main display).

March 5th Ventura was updated to 13.7.4. I subsequently installed MS Teams as Skype is going away. Now, unless I have the laptop cracked open about two inches, the Dell monitor won't display and gives me a message about the display settings. "The current input timing is not supported by the monitor display. Please change your input timing to 1920 x 1080, 60Hz or any other monitor listed timing as per the monitor specifications.'

The S2421HN is connected via HDMI to a small hub, which is connected via USB-C to the frontmost port on the right side of the MacBook. That hub also has a connection for my USB keyboard, a USB camera, and a wireless mouse.

The Acer is connected to a VGA to USB-C converter, which is plugged into the rearmost port on the same side of the MacBook. It only has VGA and DVI-D In capability.

The MacBook only has USB-C ports, of course. 

Performed some tests suggested by Dell Community:

For each separate test, I turned everything off, and detached both monitors. I then turned on the MacBook, attached the singular monitor and turned it on. I checked the Display settings both with the MacBook closed and with it opened. 

Test 1: 

The Dell worked fine when it was the only monitor attached to the MacBook. It showed as the only display in settings when the laptop was closed, and as an extended display when the laptop was open.

Test 2:

The Acer worked fine when it was the only monitor attached to the MacBook. It showed as the only display in settings when the laptop was closed and as an extended display when the laptop was open. 

The MacBook is from 2017 but has behaved itself until now. The S2421HN is from 2021, and the Acer is from 2015 (I had no idea it was 10 years old). The three items have been working fine together until a couple of days ago. 

I have uninstalled MS Teams, but that did not help.

I cannot figure out how to get back to Ventura 13.7.1, where the monitors worked fine.