I think ADSB data is excellent provided its limitations are understood and there is no better source available. In the case of a GA aircraft with no FDR or CVR it makes a lot of sense to use data that is available. From what I’ve seen over the years in this forum
DaveReidUK, and others, have a good understanding of the strengths and weaknesses of data from FR24 and similar sites and are capable of using it responsibly. Caution just needs to be taken that we don’t read too much into single data points etc. in fact the same caution needs to be taken with FDR data, the difference is that we get FDR data after experts in the field have studied it and so we’re not just handed the raw data to make of what we want, it tends to come with an expert narrative attached.