Can confirm, Dell’s docks work great because they just have to provide high-quality docks to their business customers (such as my company).
The only complaint I have is that some of their dock (dunno if it’s the 6000 series or other ones) use DisplayLink when you connect multiple monitors, which is a closed protocol with shoddy support on Linux (according to some colleagues it has gotten better, but YMMV). Everything else works has been working perfectly for years though.