I'm assuming you're upgrading to another Mac desktop, and not to a laptop. If so:
If your budget allows for it, I would recommend a Thunderbolt 4 / USB 4 dock, not one of the USB 3 docks. For example, Apple effectively endorses
this dock. Or what you could do is what I've done, which is to buy a Thunderbolt 4 / USB 4 hub, and then hang an additional USB-C hub off it.
For an external SSD, I would recommend a separate USB 4 enclosure with a good heatsink-like design, paired with an SSD. This will not only be much faster than a USB 3 SSD, it will likely also be more reliable.