Replying more to the original post than to the comments.
There's a good reason to increase the dose to or towards the standard maximum dose, and the science backs it up.
Most people on these meds have significant obesity, which doesn't apply as much to bodybuilders, younger people, or those who are just overweight. But people with long-term significant obesity are often at higher risk for heart disease, stroke, high blood pressure, impaired glucose tolerance or diabetes, high cholesterol, and low exercise levels.
GLP meds (less proven for retatrutide) reduce the risk of heart attack, stroke, heart failure, cardiovascular death, and death from all causes. They also lower blood pressure, blood sugar, and cholesterol. Since these are the main causes of death and disability as we age, GLP meds can help you live longer and healthier. Semaglutide's effective doses are 2.4mg or lower (if not tolerated), and Tirzepatide's is 15mg. The improvements are partly from weight loss, but the reductions in these levels and events happen even without much weight loss.
GLP meds may also reduce the risk of Alzheimer's and some cancers, but they might increase the risk of thyroid and kidney cancer.
Lower doses still have benefits, but they're likely smaller. Proving these effects requires large, long, and expensive studies, so it's unlikely they'll be done at lower doses.
TLDR: Taking GLP meds long-term reduces your chances of dying from bad things as you get older. There's no reason to believe lower doses are as effective.
Increasing doses slowly is generally a good idea, especially without medical supervision (which is true for many here). But for older people with significant obesity, there are good reasons to reach the standard maximum dose.