Are you plugging into a different port? I was having a similar issue with waking from sleep after being disconnected and reconnected. Then I realized I was plugging into a different port each time, and once I set the position for the displays for each port I never had that issue again.
Might be partly due to plugging into different ports as somebody mentioned, but it does seem to happen randomly for me too. But I found this tool yesterday that makes it a lot simpler to solve https://github.com/jakehilborn/displayplacer - annoying that it doesn't work properly out of the box, of course
I also have a TS3 and my experience has been similar. Quite solid. At one point I was having issues with a monitor being recognized and thought it was the TS3, but with some tinkering it turned out to be a quirk of the monitor (sometimes it just needs a full power cycle, even when no dock is being used).
I have a TS3+ with an XPS 15 9500, it's a nightmare. With only 2 monitors plugged it works well, but when you plug keyboard mouse and webcam it starts randomly dropping the whole usb stack.
I guess that thing works only on macs (for one you can upgrade the firmware only on macos).
I can vouch for Caldigit for both Mac and Windows. Been using them since the start of covid.
One of the worst docks I've used was the Dell ones. With those I've had. 50/50 chance the Ethernet will work. And if you do connect expect to drop out.
We have tested all the thunderbolt dock we could find. The only ones when we managed to have 2 screens working on Mac, Windows and Linux were Lenovo's (non Mac computers are Lenovo too, not sure if that matters)
