[Electronic M]

Your understanding of superheterodyne operation is wrong I'll explain it at the end.

IF alignment and Acoustics are 2 different concepts that are only LOOSELY correlated.

Ideally with IF alignment, you are looking to get the max gain while trying to keep enough bandwidth for the audio spectrum and (more so on FM) achieve a flat response. IF stages have different audio response curves between AM and FM and Between AM sets designed before and after AM Stereo was established. Theres also different audio curves for AM transmitter Pre-Emphasis depending on if the station is Voice, Mono, Or Stereo music.
Pre-Emphasis and De-Empahsis in radio are Similar conceptually to the RIAA equalization curve for LPs...Basically, if you emphasize (the most noise suceptible) parts of the audio band before transmitting over a noisy medium then de-emphasize them at the receiving end to return audio equalization to normal the De-emphasis reduces noise thus improving the signal to noise ratio (or in LPs reducing record dust/scratch noise).
Alignment can't change a station's preemphasis, It can compensate a bit and at absolute best only try to be a compromise between what is best for each different station. Audio frequency response of the IF is fairly baked into circuit design so trying to adjust an existing reciever for more than an optimization of gain and bandwidth isn't something anyone does (trying would probably drive ya mad).

Osc adjustment is there to try and make the numbers the dial is pointing to accurate.
RF stage adjustment is to optimize sensitivity to weak signals and make sure that sensitivity is even across the band.

Preamble to Superhetrodyne opperation:
First some info on RF and modulation, Radio frequency is a single tone far above human hearing range in consumer sets (though the Navy uses IIRC 75Hz to communicate with submarines in deep sea). We make that tone carry information by varying its amplitude (intensity) or its frequency instep with the changing instantainious value of the information we want to send. AM Modulation makes the curve formed by the peaks and the curve formed by the valleys of the carrier waves match the shape of the modulating audio signal. To recover the audio from an AM carrier you rectify the carrier at the detector which gives you high-frequency DC spikes who's peak values trace the curve of the audio modulation...A filter is used to remove the remaining RF and smooth out the RF rate jaggedness of the audio giving a nearly perfect reproduction of the audio waveform sent. Perfect AM modulation is impossible changing the carrier amplitude at some frequency also changes carrier frequency. It is possible to modulate the peaks of an AM signal with one modulating signal and the valleys with a different modulating signal creating AM double sideband stereo (which was a thing at least while the AM stereo format wars existed in the 80's). Normally both sidebands are modulated the same for mono. Perfect Amplitude Modulation is impossible the carrier frequency changes with the frequency of the modulation. Thus you need a range of frequencies on either side of the carrier to accommodate the modulation frequencies. In mono AM the bandwidth you need is 2X the audio bandwidth you want or are allowed to transmit.

How a Superheterodyne works:
A Superheterodyne is designed to take a limitation of RF amp design and change it into an advantage. Basically an RF amp has a Gain-Bandwidth product...In other words the if you want a ton of gain you have to make the bandwidth it can operate at really small, but if you want a lot of bandwidth you can't have much gain (gain being a measure of the increase in signal an amp produces). So before the Superhetrodyne was invented radios were TRF (tuned radio frequency) basically around 3 Amp tubes that could amplify the entire AM band with adjustable filters between each amp to select the station, the output of the amp chain feeding a detector.
What A Superheterodyne does is convert a selectable RF carrier of variable frequency and convert it to a fixed frequency.
It does this by mixing the carrier frequency with a local oscillator frequency to Produce an Intermediate RF Frequency (IF). Basically when you mix 2 sinewaves (carrier which we will call Fc, and the Oscillator which we will call Fo) we get 4 sinewaves....Fc, Fo, Fc+Fo, and Fc-Fo. Also the Fc+/-Fo outputs retain the modulation that Fc had before the mixing...So you've magically made the carrier a lower and a higher frequency. RF amps usually work better at lower freq so IF is usually chosen to be the Fo-Fc. Basically a superheterodyne varies the oscillator and such that the mathmatical equation Fc(of station)-Fo=IFfrequency is maintained at all times. Theres also a AM preselector filter that tries to reduce all other stations but the one the osc is trying to convert to an IF frequency.
This system results in cheap radios that are extremely sensitive (ie high gain) to weak/distant stations and better at separating adjacent stations on the dial from eachother. The IF amps only need to work over ~1/100 the bandwidth of an RF amp that covers the whole AM Band so theoretically the same tube could make 100x the gain if used as an IF amp instead of an RF amp. Each IF stage usually has 2 tuned filters that reject all frequencies outside the IF band...The more filter stages the stronger the rejection of signals (other stations, atmospheric noise, etc) close to but narrowly outside the band of the desired station....Most radios have 2-3 IF stages plus 1-2 filters in the RF stage and the filtering effect of the local osc frequency conversion which is far more than the 3 filters in an average TRF.

You can demodulate an AM signal by mixing a fixed amplitude RF signal of the E-X-A-C-T same frequency and phase as the station carrier, but that requires PLLs which weren't up to the task in the tube era (unless you wanted your radio to cost as much as your house).