Peoples individual responses to GLP drugs seems to be very variable, both side effects and useful effects. The advantage of starting at lower doses than standard is to reduce the risks of unpleasant side effects that happen suddenly. One person might get mild nausea at 8mg and another vomiting at 2mg , but the standard start doses were chosen for a reason, for reasonably low chances of severe side effects on starting. Starting at 1mg for a couple of weeks is reasonably sensible but not essential, starting even lower is probably in most people a waste of time.
People who are not overweight or only mildly so do seem to sometimes get stronger responses to lower doses. And in that case low doses and slow increases make sense, mainly as any health risks from taking the drugs are not counterbalanced by the health benefits of treating obesity. And usually those people are not going to need very high doses anyway.
I am not sure that how slowly you build up the doses makes any difference to the dose that will cause side effects in that person, which you can only find out by starting them and seeing what the effects are. Getting mild side effects at a lower dose is an indication that they will get worse with dose increases, which can be used to slow down dose increases, and is likely the main advantage of slow small dose increases. Tolerance to GI side effects like nausea is usually a fairly slow process, probably slower than even very cautious dose increase plans.
Interesting, that is the third person on this forum describing a panic attack like episode from starting reta, assuming it is a different person, it is not reported in the studies and probably should be.