The chosen answer is not quite correct for the 8.0" 350.
In step 8 of the motherboard replacement guide for the 8.0" Galaxy Tab A 350, there is a protective cover plate for the USB port that is removed via two 3 mm screws. There is no flex cable. (It does appear that other Galaxy Tab models do have flex cables, probably hence the confusion. The YouTube video cited is for a different model: also a Galaxy Tab A, but the 9.7" T555 rather than the 8.0" T350, I believe.)
HOWEVER: once the protective cover is removed, what is revealed is the back of a standard USB port, with its four soldered anchor points. Once the motherboard is completely removed (see my comments on this procedure--some connectors need to be disconnected first that are not mentioned in the guide), and flipped over, the USB port is seen to have seven pins as well as the four anchors, which must be microsoldered to their pads. Only the middle three of these are really small; the other four are (relatively, for microsoldering) fairly large.
But this is in fact a rather standard micro USB port replacement, soldering and all. There's just a screw-on protective plate over it on the motherboard.
IN CASE IT SAVES SOMEONE ELSE: please pay careful attention when removing the back cover of the device at the very beginning of this procedure. If you think of it as removing the back cover (and not the front display) you'll be OK. I inserted my spudger between display and motherboard rather than between motherboard and back cover, and succeeded in shattering my display despite a pre-installed glass display protector. Sigh...
AND, IN CASE IT REALLY, REALLY SAVES SOMEONE ELSE: replacing the USB port on my Galaxy Tab A, although it provided me much microsoldering practice (and Galaxy Tab disassembly practice), did NOT solve the problem of a loose connection between port and cable. What did that was (very carefully) clamping down on the back of the USB port with a pair of pliers, and then double-checking continuity of each pin with a micrometer to make sure I hadn't broken any connections. This still requires removing the motherboard and protective USB port cover, but does not necessarily involve microsoldering, and does not require a new port.
(I attempted to solve the connection problem at the cable end, by raising the two connectors on the back of the cable connector with a needle, a procedure I found on YouTube. In my case, this only resulted in a red X through the Samsung charging icon--Samsung's signal that there is a connection, but charging is not going properly. Still, might be worth trying, since it's so much simpler and less hazard-prone...)
Samsung Galaxy Tab A Motherboard Replacement