Any way to identify cycles within data sets, set start stop points, then overlay the data?

What I'm trying to do is find the repeating cycles within the pressure data for each channel (there are 6 different channels in each data file), set start / stop points where each channel's cycle starts & stops, then align those points to overlay the data. I have a number of data sets that are pressure values for different 'channels'. The time data that's associated is not relevant, and the sync data is not always correct. Below is a picture of one cycle of all 6 channels (with all the noise). You can see the variation in the data (cycle to cycle the shape of the peak will also vary). I've also attached an example file as well as the code I've been trying to get to work, but am running into a lot of issues because of the fact that the channel data is not all the same length and in cleaning up the noise it creates NaN's

You can also see in the code some attempts to overlay the cycles by using the sync data and adding it where missing, but because each cycle isn't exactly the same length, doing it this way causes the overlapping cycles to shift off of center.

Any thoughts / suggestions? Thank you!!