By EQing... And that's possible if you have the CSV file of the frequency response measurement of said earphone. What earphone are you talking about?

Look into squig.link and use the AutoEQ feature there, you can compare graphs, easily parametric EQ to a specific target, etc.

Parametric EQ with squig.link, AutoEQ, (Peace) Equalizer APO, et cetera: https://www.reddit.com/r/headphones/comments/11yd6rh/im_a_noob_and_use_spotify_eq_just_had_some/jd772sw/

You can do (parametric) EQ with $8 Neutron Music Player or UAPP on Android. If on PC, the free (Peace) Equalizer APO. There are free apps on Android(/Apple) that can also do a good enough job, but most of them have those graphics sliders instead of parametric or just plug the numbers in EQ. EQ can also be used to help with channel or ear imbalances.

There's also the free Wavelet app that has the AutoEQ available now. And other free apps for more simple graphic sliders EQ, etc.

Try cheap ear tips like FiiO HS18, TRI Clarion, Spinfits, etc. too. Try parametric EQ first as it's free or cheap, lol.

Cheap ear tips (basically FiiO HS18, Spinfit from some AliExpress storefronts, Chinese websites like MTMTaudio/et cetera, and so on) and possibly better soundstage: https://www.reddit.com/r/HeadphoneAdvice/comments/1157giz/upgrade_imaging_with_balanced_cable_iem_or/j90a003/

How to put ear tips on wide nozzles (basically aim it at different angles and force it, be careful not to overdo it as it can damage the core/stem/stalk/etc. of the ear tips): https://www.reddit.com/r/HeadphoneAdvice/comments/125dhs7/i_feel_so_dumb_asking_this_how_do_i_replace_the/je3yez7/

EQ is free, and while resources like squig.link are very valuable learning to E by ear is really handy. EQ APO and Peace are free on Windows, and Wavelet is also free on Android

Eq for sure, but you might want to consider the 7hz zero or truthear hola for the future