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If the distortion is the same at low and high audio levels which it appears to be in the photos then I suspect the problem is in the audio circuitry. A DC bias problem in the final stage usually affects the modulation waveform mostly at high audio levels. Also, aren’t the second and third waveforms the same?
Since you know this is distorted then you know how a proper waveform appears but just for reference here’s a photo of the audio and RF envelope from one of my transmitters which shows that even simple transmitter circuits can perform well.