In principle, this should work, provided your Dell laptop has USB-C (Thunderbolt) and the docking station is connected at the rear left.
But as for Lenovo, unfortunately they do their own thing, I would only buy Lenovo if you already have Lenovo and otherwise go for the docks from HP, Startech or i-Tech.

I only have Thinkpads at home. But I could also use my mobile phone to the full.

What went wrong for me was that you plug the USB C cable in at the back. I had plugged it in at the front first.

I had also first bought an unbranded dock (Lenovo laptop with Hama dock).
I had problems with it, which also the support could not help me.
I then bought this Lenovo dock for my Lenovo laptop on the recommendation of the Digitec salesperson and it has worked wonderfully ever since.
PS: As far as I know, you can combine all screen brands with this dock, it just needs a corresponding HDMI connection / cable.