EDR is modern technology. Hence it can detect and clear threats, so when using EDR you don't need to use antivirus.
When both are used they will slow the machine and sometimes cause technical issues.
EDR is a more advanced program that collects data from the nodes and also does analysis and identifies where the threat is originating from.
Antivirus or AV is a single program that is used to scan files and OS for known threats like Trojan, worms, and Malware.
