I have a moto and hate Dolby Atmos for headphones

Instead, turn that shit completely off and get an app called "Wavelet". Use the AutoEQ function with your headphones model.

The purpose of the AutoEQ is to return audio to "studio reference" EQ based on the measured frequency response curve of the model of headphones you have

If it still sounds bad to your ears then there are two possibilities:

1. The hardware is defective. You could try getting it replaced

2. Your old phone has settings that were so bass-heavy that your sense of what's "right" has changed

I recommend trying out AutoEQ on another device that you know works. Make sure that all other audio processing is disabled when using AutoEQ. This will give you a good baseline to compare against

On Windows you can get AutoEQ using EqualizerAPO + HeSuVi (a front-end for setting up EqualizerAPO to enable custom virtual surround sound and AutoEQ)

Not am audiophile or anything but i do like having good quality sound for listening to stuff so ive gone down the rabbit hole a couple of times.

If the audio sounds bad on more than a few headphones or speakers, could be the phone is bad out of the box. Does happen. I had a phone that was supposed to have accidental touch protection for when your phone is in your pocket but it would still turn on and mess with stuff while in my pocket.

I would recommend you check on a few diffrent speakers to see if theres any noticeable difference in quality. Headphones vs another pair or speakers in your house vs your cars speakers. That should give you an idea if its the phone itself or your current audio devices.

Are they Bluetooth headphones? If so, check the protocols supported by your phone, and by the headphones, e.g. aptX vs LDAC vs SBC. It's possible that it's not a "downgrade" on the new phone, but rather an upgrade to a better protocol, but unfortunately not one compatible with your headphones, so you end up using a low quality fallback.

You may also want to check your settings, and see if you can select a specific protocol. Sometimes a lesser protocol is chosen by default, if the better protocol uses more battery. This may be available to you in the phone settings, or as an option in an app for the headphones (e.g. my Anker Soundcore app allows choosing between two protocols).

I use one that probably won't be well liked around here but it's called EZ Booster. It's got ads which is annoying but it has an equalizer and can hella boost sound volume, which I was having issues with when playing audios from my browser. I haven't played with the equalizer much but the volume booster on its own has made a huge difference for me.

Yeah, look for an equalizer app.