Assuming you started with a new 2nd generation recoil spring and good, late-design magazine springs here are a couple of thoughts:
1. Those comp ports look pretty large - large enough to bleed enough gas off that the slide velocity is noticeably slowed. If that's the case, a used - weaker - recoil spring would help.
From the top side the workmanship looks great, but check the top of the barrel and the underside of the slide to make there are no burrs or sharp edges that can impede the action of the barrel / slide during firing.
2. Timing is critical on any auto-loading pistol, and small guns like the R9S just don't have much "margin for error".
BTW: Before getting set up with 2nd generation recoil and mag springs, I had a few failures to eject like you have pictured in your post. Without a slide lock, that sort of jam in the R9 is a bit of a bear to clear.
I came up with a simple clearing routine: Push down on the rim of the top round in the magazine with a pencil, pen, twig, even a spent shell (but not your fingertip!). The slide will go into battery, or close enough, for you to remove the magazine and rack the slide to dump out the spent casing in the chamber.
Good luck. Your gun looks great, but until you get it to reliably go "BANG!" it's just an expensive rock.
And welcome to the forum.
Steve