I often read recommendations that dissuade people from using an AV together with a companion AV (commonly mislabeled Anti-Malware by the manufacturers themselves), whereas nobody has a problem with combining an AV with something more aggressive and invasive, like HMP.Alert, Sandboxie, MBAE and the likes. In my opinion the latter combination has much more conflict potential.
Sandboxie is the mother of incompatibility (not meant as an insult) with other products, aside from Windows Defender. HMP.Alert has behavioral and exploit protection, which most AVs have today. Ever wondered what happens when EAM's behavior blocker and Alert's behavioral dectections (cryptoguard, process protection) might be triggered at the same time? Ever wondered what happens in case of an exploit, when both your AV and your companion anti-exploit software proactively watch for exploits?
I don't think that combining MBAM Premium with EAM, for example, is such a conflict prone combination.