Well, I just remember that back in the Raspberry Pi 1 days (yeah, long time ago ...) the USB powering circuit was REALLY sensitive. It's supposed to be fixed since Raspberry Pi 2 but you never know ...
The 3A is the total Power Supply rating ... The Raspberry Pi should have its own USB Powering circuit. From this Thread it looks like limit might be only 1.2A:
What happens if you disconnect (physically) the display, then disconnect-reconnect the 2 USB adapters ?
Try to see if you get anything in the logs, particularly kernel log and "dmesg". Maybe some driver acting up ?
Does it work with only 1 USB adapter instead of 2 ?
I'm usually not fond of not-isolated adapters. Any chance the USB port got damaged ?
It's definitively weird that it worked for 4 days then no more (only for a brief moment). Anything significant changed ? Potential noise sources ? System update ?
My raspberry Pi 3 is actually powering 6 USB to RS485 dongles, 4 in an unpowered hub and 2 directly. No issues.
Even worse, the Pi is powered from a USB connector on the Dell tower that is running HA. It does complain about power dips but I'm not seeing any practical problems so far and it has been this way for 10 months now.
Second one has less wireless stuff involved and less points of failure. I use a WYSE 3040 instead of a Pi (not tested the Pi 5 yet though...) and found it much more stable.