While background hum and certain continuous-type noises are relatively easy to isolate and reduce with special digital filtering…
Reverb/Echo is one of the most IMPOSSIBLE-to-fix of audio problems, second only to severely CLIPPED (over-driven) levels.
“EQ” won’t do it.
Its reverb (repetition) of the PRIMARY audio… the same frequency that you want to KEEP.
The “Noise Gate” is probably the best choice, but it will surely PUMP if its set high enough to have very much effect on the reverb. (So it could end up making many tracks sound worse.)
Whatever you try will adversely affect the overall QUALITY of the audio being “fixed” and be very noticeable to the listener (especially compared to any “good” audio in the same production).
I know that re-recording is not always possible,but once you have a poorly-recorded audio track, under many conditions, it just can’t be “fixed”.