https://www.amazon.com/dp/B00M7X6XNG/ref=cm_sw_r_cp_awdb_t1_3tJ6CbHXEYB1E
Those are pretty slim and looking nice. Make sure to get the correct angled version.
That’s not it, it’s close though. You need one with a micro USB port and regular port. There’s one linked in the comments, I’ll try and find it.
:edit: this is it, the left angle one. https://www.amazon.com/dp/B00M7X6XNG/ref=cm_sw_r_sms_c_api_i_heD7CbNM2KZWY
I just tried to see if it would charge my phone and it does. Naturally the "quick-charge" didn't kick in, but it did start standard charging. Another way to test is to have one controller plugged into the player 1 slot & the 2nd controller plugged into the OTG cable. Just boot into stock and see if the 2nd controller is able to control the system when connected via the OTG usb slot. If not, then it's either the OTG cable - or not enough power is being supplied to the cable/system. Can you try a few different power sources to rule that out if you haven't already? Try a couple different phone chargers, the USB port on your TV if it has one, and also a couple different USB ports on your desktop/laptop. If all of those sources still fail to power the controller or charge your phone.... then it's absolutely the cables & I'd get a refund and either order the same cable I did from the link I posted above, or you can try your luck with one of these:
For the top one be sure you get the Left-Angled version. For the bottom one, Right-angled is correct. Don't know why some manufacturers label them oppositely. Shrug.
https://www.amazon.com/CHENYANG-Adapter-Galaxy-Tablet-Angled/dp/B00M7X6XNG/
or
https://www.amazon.com/Fun-Home-Female-Adapter-SamSung-Features/dp/B013ENTY9M/
Edit: Here's another cable people have had good luck with.
I got this angled adapter, works well. Make sure you get LEFT angled, not right.