What seems to be the problem?
In the meantime try this (RH only for the passage in the picture):
1. Ignore the lower voice (quavers, stems down) and work only on the groups of four semiquavers (there are four groups in the picture). Fingering is 4543 – 4543 – 4543 – 4543. There should be no problem with each group of four semiquavers. It is the change between groups that is tricky. You must displace your hand to the left and land on the 4th finger on the first note of each new group of four semiquavers. Does this make sense?
Let me try again. Start by playing CDCB with fingers 4543. This should be easy. Now, the next note is an A and your whole body will want to play that A with the 2nd finger. You must inhibit this impulse, and instead play the A with the 4th finger. The way to do that is not to reach with the 4th finger for the A since this will be a very awkward passing over the 4th over the 3rd. Instead, leave your 4th finger where it is and use your arm to move the whole hand so that the 4th finger is positioned on the A. The same movement applies to the next groups.
2. If this is still impossible, break the passage further and work only on the hand displacement, i.e. practise only the notes involved in the displacement: B (3rd finger) to A (4th); G (3rd) to F (4th) and finally E(3rd) to D (4th). Once you can do this smoothly and accurately, put back the other notes. Once you can do this accurately and smoothly put back the lower voice. You will see that the hand displacement you did above automatically places your fingers in the correct position to play the lower voice chords (you may need to calibrate and fine tune the movement).
3. Although the lower voice is supposed to be held, do not stretch your fingers trying to negotiate it. Instead, use the movement of the hand to release the lower voice. For instance, in the first group of four semiquavers, as you play the chord (4th finger on C), do not try to stretch the fifth finger to reach for the D while holding the DF#. Instead “roll” your hand to the right so that at the same time that the 5th finger hits the D (as a consequence of this hand movement), the DF# is released (as a consequence of the same movement). So one single smooth movement takes care of both, releasing the lower voice and pressing the D with the 5th finger.
4. Finally add the left hand.
5. Proceed like that for any similar passages.
I am not sure if that is what you want (maybe you already tried it all). Keep in mind that describing in writing these movements is always misleading, demonstration is always preferable
I hope it helps.
Best wishes,
Bernhard.