Its a matter of headroom.

The loudest you can play at the digital side is called 0 dBFS. If you exceed this level, you get digital clipping.

Often recordings do have sufficient headroom e.g. 10 dB so you can boost without hitting 0 dBFS. However, there are also recordings with very little or no headroom. This is typical for the loudness war. Even the slightest boost will result in distortion (digital clipping).

As already mentioned by others, a simple strategy is not boosting but lowering. If you want to emphasize 400-2400, leave them at 0 and lower the rest.

Another solution is simply not using the Spotify EQ or the EQ of any other app as you have to tailor each app. Just go system wide. https://www.audiosciencereview.com/forum/index.php?threads/eq-software-for-windows-linux-macos-ios-ipados-and-android.18450/

If it comes with a pre-amp, you can boost to your harts content and simply use the pre-amp to compensate for the highest boost. In case of Win you can also avoid distortion caused by resampling signals close to 0 dBFS.