I'm not telling you to swap out the head unit, there's many workarounds nowadays. Some cheap, some expensive.
Cheap way would be to leave the head unit as is as a decoration and HVAC controller, still functioning but will not be used for audio. You would give up bluetooth calling capabilities this route as well. You'll be dayton audio dsp 408 and a bluetooth dongle (will run you about 180 total for those two) and pretty much hook up power, ground remote and the dsp tucked away hidden somewhere will and will act your head unit. APTX HD is lossless bluetooth and trust me, even SQ judges couldnt tell the difference between CD and APTX HD. The signal is not only flat, its amazing off the batt due to the high quality dacs of the dsp meaning you get massive amounts of detail and clarity vs using anything connected to your stock head unit, night and day difference off the batt. The DSP has 8 channels of output, each channel has 10 bands of parametric EQ, so your tweeters get 10 bands, mids get 10 bands, midbass/rears get 10 bands, subs get 10 bands. Each channel has bandpass crossovers that you can choose any frequency and any slope you can even think of. Each channel has time correction as well which is key. This costs not much more than an LC7I but is FAR superior. If you want to keep bluetooth calling and use of the head unit as the audio source, you can just use the speaker level inputs of the dayton as well. Definitely this choice over the shitty audiocontrol dinosaur tech lmao.
the more expensive option would be a 600 dollar DSP with factory de-equalization capabilites like a jl fix and twk or an audison bit one or helix dsp, works the same way as the LOC in terms of getting signal from your speakers, it sums up the signal and then has input EQ software that flattens the incoming signal and recreates a flat signal. These have everything the dayton has audio features wise just no direct bluetooth streaming on some of them. The dayton only signal sums, but does not flatten incoming signal if using the speaker level inputs.