You seem to be working from base principles without consulting the literature.

https://pubmed.ncbi.nlm.nih.gov/28991040/ Conclusions: Low muscle strength was independently associated with elevated risk of all-cause mortality, regardless of muscle mass, metabolic syndrome, ...

https://www.amjmed.com/article/s0002-9343(14)00138-7/fulltex... Muscle mass is associated inversely with mortality risk in older adults independently of fat mass and cardiovascular and metabolic risk factors

And specifically GLP-1 usage is associated with significant loss of lean mass: https://pubmed.ncbi.nlm.nih.gov/38937282/ In some studies, reductions in lean mass range between 40% and 60% as a proportion of total weight lost ...

This might be a good start. There is quite a bit of material here and as might be expected much of it is fairly recent and gets a lot of this kind of skinny equals long life feedback that isn't strongly supported by clinical data.