Im looking to build my own router. Basically an android phone via usb, and usb wifi card and usb hard drive. Currently im using a RPI4, however I remember the USB on the pi's is rather poor.
Are there any small SBC's that would fit the job better?
These are all usb 3.0 devices.
nanopi? mini oc?
If you want your diy router to be a wifi access point, be sure to check that your selected wifi solution supports ap mode and is known to run stable. There are lots of reports on this forum about such problems, including failures at high transfer rates and dongles that won't do ap mode with the drivers available in OpenWrt.
Can you describe what is "poor" about the Pi's USB as it relates to your usage? There are several potential issues (power budget, number of 3.0 ports, etc.), but we need to know what limitations you are trying to address.
That said, @spence's advice about USB-wifi adapters is critical. You would likely be better served by a proper AP if wifi is important to you. There are lots of good all-in-one router solutions that have excellent OpenWrt support, often with better/cleaner mechanical design and more cost effective than using a Pi or other SBC to "build your own" router. Don't get me wrong, there are some great SBC options, but adding a USB-wifi adapter will likely result in sub-par wifi performance at additional expense relative to a purpose built device.
Of course, a great option would be the OpenWrt One.
Make sure the device has USB 3.x Gen 2
USB 3.1 Gen 1 supports speeds of up to 5Gbit/s while USB 3.1 Gen 2 supports speeds of up to 10Gbit/s.