Don't see how IEMs are giving you tinnitus, it's usually due to bad listening habits (listening at loud volumes for long periods) historically and you don't get it overnight or over a short period of time but prolong exposure.

Getting headphones or loudspeakers as an alternative won't solve the issue if you already developed tinnitus.

Besides, this thread relates to ampflication and DAC recommendation. Headphones & IEMs are on the other pinned thread.