Run it metal to metal or use a thin film of RTV (sensor safe!!) between the engine and muffler. I use RTV all the time. Never a worry if a little oozes in. Just make sure the rtv cures before running the engine. Otherwise it might blow out and leak.

Oh, and DONT use paper Gaskets!! you most certainly will have either a loose muffler, or NO muffler upon landing.

That’s an old wives tale AFAIC. I cannot say I’ve ever had RTV snuff a plug out - I even tried to force it to happen. The engine just blew the bits of silicone out the exhaust. (I stuck a dozen chunks of dried RTV down the carb with the engine running both at full honk and at part throttle).

I’ll tell you, even the highest quality engines leak between the exhaust port and muffler. I would always recommend a thin layer of RTV on the muffler. It’s not rocket science and it does make a significant difference most often. YMMV, but probably not by much.

I’d not want to use epoxy. RTV is way easier and cleaner, and bare metal to metal easier yet. But I guess if it makes you happy.

I tested the myth of silicone killing a plug by taking dried rubbery chunks and dropped them down the carb. Some bits took longer to blow out. I wouldn’t expect any device to function well if it ingests wet silicone.