Air carrier Captain reported during initial climb the Captain's side radio altimeter displayed a negative value and the flight director did not indicate correct bank angle or pitch attitude. Captain cited 5G interference as possibly contributing to the event.

Narrative

Cleared for takeoff [Runway] 27L and assigned a left turn heading 230. When First Officer (FO) called 'Positive Rate'; I noticed radio altimeter was reading -4. Cross checked FO's radio altimeter and appeared to be operating normally. When I called heading selected 230 the flight director only commanded a 8 degree turn. Above acceleration height; I asked the FO to reference my radio altimeter. The FO observed -4 and then a blank alternating on Captain (CA) radio altimeter; while FO's appeared to be ops normal. All the while the flight director CA was not commanding a lower pitch for flap retraction. Crew ran QRH checklist for Radio Altimeter Failure and reported possible 5G issue to ATC. We suspected 5G interference because; although FO's RA appeared normal; the 8 degrees AOB and wrong pitch attitude commanded by flight director appears to correspond to the additional info note from QRH procedure. Ops normal approach and landing ZZZ. Suggestions. Need more information on 5G affects on Commercial Aircraft.