There are options to connect external storage and mid- and upper-end printers to the network.
Examples of Network Attached Storage (NAS) include Synology NAS arrays and FreeNAS. Synology NAS also offers a variety of other network services and features beyond storage services, all provided from the NAS. As can FreeNAS. Examples of network-connected printers include the Brother MFC series, and similar models from other vendors.
Larger direct-attached storage on Mac often involves Thunderbolt storage, with the older first or second-generation Thunderbolt connectors, or with third-generation via the USB-C connector. Thunderbolt locally will be faster than NAS.
Promise Pegasus arrays are one of many examples of this.
Closer to what you’re asking for here, Satechi offers a chin dock for iMac, and there are many other sorts of docks around, many of which will work just fine with iMac and USB-A devices.
Accreting piles of USB-connected widgets tends not to scale, as you’re now discovering. (It’s better than it was too, as USB 3 is decently speedy, and power control has gotten better. Earlier USB was much slower.)