I think you’re overcomplicating this for yourself.
To resize a juce audio buffer to hold 1 second worth of samples, you would call setSize (2, 44100). This tells the buffer, I want 2 channels, each with 44100 samples.
Then, when doing your audio processing, you can write any code you want that references sample #s 0 to 44099 (ie, “numSamples-1”) and run that code on any channel of the buffer. Because every channel will have a sample 0, a sample 1, a sample 2… All the way up to 44099.
When speaking about buffer length, we typically give the number of channels and the number of samples in EACH channel. So, for a 1 second long 2 channel buffet, it is wrong to say that it is 88200 samples long – the reason why is that the # of samples you can actually access and actually use on each channel is 44100 - NOT 88200. So attempting to access any index greater than 44099 will give you an addiction failure or a seg fault.
A one second audio buffer at sample rate 44.1 kHz has a length of 44100 samples. That is how many samples are in each channel of the buffer.