While I have never tried it personally, DXM+psychedelics is said to be a very intense experience. Only consider this combo if you are very experienced with both substances indevidually and with strong trips in general.
I would recommend against this combo.
The DXM could potentate the CNS depression of the opiates, increasing likelihood of overdose. Also, both drugs can cause nausea and vomiting coupled with a lowering of awareness, so the risk of asphyxiation could be increased as well.
If you must pursue this combo, lower than usual dosages of both drugs. Be especially careful with the dosing of the pod tea, as potency can vary greatly with every new batch brewed. Stick to a threshold dose of DXM, lest I imagine such a combo would lead to feeling too overly fucked up to be fun anyway.
DXM+Cannabis is the combo I would recommend. There is a definite synergy between the two. The combination is more than just a sum of it's parts, I would even go so far as to say that the cannabis makes the DXM a more complete and satisfying trip. The cannabis also makes the trip feel much stronger without increasing negative side effects. I actually wouldn't take DXM without some cannabis to smoke at 60-90mins after dosing.