I use a bunch of Lenovo Thunderbolt docks, with both Macbooks and Thinkpads. The older models go for as little as $20 used nowadays. I had to update the firmware on the really old ones, but after that they work flawlessly and let me connect 2x4k60 monitors.

I have a ThinkPad Thunderbolt 4 Workstation Dock - Type 40B0.

Last time a firmware update came out I couldn't run it from my Lenovo laptop. I had to use a non-Lenovo one. Really made me angry about their quality control.

Next to that the dock has this weird behavior when the laptop is asleep, the monitors wake up every 5 minutes.