The inner voices are shared between the hands depending on which one can reach the notes. For comfortable execution of this type of legato counterpoint, your wrists and elbows need to be relaxed. Then the hands will adopt appropriate hand positions – usually with the wrist raised – for pivoting on the thumb in m. 21 or playing parallel thirds in m. 27, for instance. *Upper LH voice in mm. 18-19 and 25-26 can be omitted.
For inspiration and reference, it’s always useful to listen to recordings: there are plenty of orchestral ones out there and my piano duet version of is also available, released on Grand Piano records in November 2022.