I use an inexpensive 4-port powered USB 3.0 hub from Anker. Not very rugged, but it does the job. The only issue I've ever had relative to Stellarmate is that the Serial Port Assistant gets confused and won't consistently assign port names. Probably important to note that I use an iOptron CEM60, which itself has a built in non-powered USB 2.0 hub. In my configuration, the CEM60 connects to one port on the Anker hub, and the iOptron hub (imaging camera, guide camera, focuser) connects to another port on the Anker hub; this then plugs into the Stellarmate.
I'm using an Anker 7-port powered USB 3.0 hub. The serial port assistant got confused on this hub, so I plug the mount (NEQ6-R Pro) directly into the Stellarmate. The hub is plugged into the Stellarmate, other devices into the hub.
INDI/KStars on Raspberry Pi 4, 4gb
Raspbian Buster with AstroPi3 script configuration
Skywatcher HEQ5 Pro Mount
Canon 600D Camera
Orion SSAG/ASI120mm @280mm Guide Scope
Waveshare Stepper Motor Board - DIY Focuser
Adafruit GPS Module
Generic Bluetooth Joystick.
Startech 7 port powered USB Hub.
Any of the startech Hubs work well, as do Anker ones.. also I have used an Orico one too...
Stellarmate OS on Raspberry pi4b
Skywatcher EQ8 pro, on steel pier
Takahashi FSQ85 & Meade 8” SCT (de-forked)
Starlight Xpress SXVR H18, SXVR M25c, Lodestar x2 Guide Camera
Pegasus Ultimate Hub V2 for all USB & Power
Pegasus focus motors on both scopes
I have had similar issues with the same hub. If I want Ekos to see the mount or the GPS USB dongle, I have to plug them into the Pi, not the hub. I haven't tried a USB 2.0 connecting cable, I've no reason to believe that would solve the problem but I'm gonna give it a whack. Important distinction about this particular Anker hub is that it runs off 12V, so you can cut the cable off its wall-wart and wire it into your battery system.
[EDIT: I now have this, and find it works well powering the RPi3B+ and at the same time my Nikon Z7 using a Case Relay. ]
120 MM Skywatcher Esprit on Celestron CGX
ZWO ASI 224MC guiding
Pegasus FocusCube v2
Nikon Z7 8256 x 5504, 35.9 x 23.9mm 4.34 um
Triad Ultra Quad NB Filter
Kstars: 1) Odroid-N2 Ubuntu-mate 20.04 2) StellarMate on RPI4 8G
The good, the bad, the ugly at sciencedowneast.no-ip.ca/zenphoto/