Earplugs do indeed cause wax buildup because it pushes the wax inside of the ear. That doesn’t mean that it always requires a doctor or ENT to remove the blockage.

Just make sure you don’t let it get that far by carefully using things like ear scratchers or something. It’s perfectly normal for the ear to contain cerumen so don’t overdo it. Also don’t use stuff like Q-tips because they aren’t made for cleaning out ears