Air carrier Captain reported possible 5G interference with their aircraft during approach to ONT airport.

Narrative

We were flying the ILS approach to ONT Runway 26R at approximately XA:50Z on Date. I was pilot monitoring. The weather was clear with light winds (night landing). There was no other traffic. There was a NOTAM for 5G interference for ONT in the current NOTAMs. The First Officer; (FO); flew the approach in NAV and PROF on the Scooby-2 arrival all the way in until we intercepted the ILS with the autopilot in APCH LAND. We had Dual Land status after the pre-land test and were cleared for landing. The FO disconnected the autopilot at around 1;000 ft. AGL; as he had briefed. Sometime just below 1;000 ft. AGL I noticed the azimuth for my (Captain) ILS becoming jittery; moving erratically to both sides; often with full deflection. I noticed the FO side was normal. At one point I got a momentary 'ILS untunable' message. The glideslope presentation for my side seemed normal. This continued all the way to landing. The FO's ILS presentation was normal throughout the entire approach. At one point; probably around 200 AGL; I saw an amber 'X' in place of my radar altimeter readout; indicating a radar altimeter failure; though it only lasted for less than one second. It was a normal landing. After blocking in I radioed the tower to tell them what happened; and asked if they had any recent reports of 5G interference. They said they did not have any reports of interference. The tower controller said he would file a report. I made an AML writeup. I can't say for sure whether this was 5G interference but the radar altimeter glitch makes me strongly suspect it could have been. The erratic nature of my ILS presentation appeared to worsen as we came closer to landing. If this had happened in the weather I am certain we would have had to fly off number 2 ILS only; with no autopilot available for landing; and consequently to higher minimums than expected. Possible 5G interference with aircraft instruments.