EOS R5 - High pixilation in low light

[lsvasan]

Hi, Shooting with my R5  in low light with ISO greater than 1600 gives me a very grainy picture.  I dont have this problem when I use my 5D Mark IV. Any suggestions on I can avoid getting a grainy shot using my R5.

[lsvasan]

I was shooting at an indoor event. Used a RF24-105 - F4   L series lens in Manual mode. No custom setting, used evaluative metering. Attached is a picture. appreciate your inputs.

Here is a link to two images:

https://www.amazon.com/photos/shared/bv7sdtbtSRiprFNUleYZuw.cVBrRvytHDVqYGNaAI_25-