ItsAllGoingToBeFine - I think the best background read on this is:
www.transgendertrend.com/puberty-blockers/
The honest answer is that nothing is known for certain. Emphatically not the answer we want to hear about any intervention, particularly not one with lifelong consequences. The available evidence is from children and young people who used puberty blockers for a comparatively short time period with an agreed stopping point (e.g., delaying early menses in girls until they are 12 rather than 8, as can happen).
I doubt anyone has conducted a case study of someone who has artificially blocked puberty until the age of thirty without crossing over to hormone therapy. For various reasons, I'd be startled if you could pass through puberty with an adult body in some ways but not in some other critical ways. At this point, I give up thinking I'd even know what happens to the adolescent growth spurt or the laying down of calcium in the bones, or the changes in body composition, or the cardiovascular or pulmonary systems in this context. There will be some developments through different pathways, but they will be lesser.
For children, it looks like puberty blockers are transitional until such time as they're ready to begin cross-hormonal treatment (if they decide to do this and depending on age and other restrictions within that country's medical system) and then the prescription and interplay of suppressors and other hormones begins.
Not sure this has helped.