This is a fascinating one.

Some things to consider, a toddler can easily defeat a baby but a 40 and 45 year old are evenly matched. There's also the question of how much is there to learn, at some point the tech tree is pretty much done - iron is much stronger than brass but maybe light-speed heavy plasma guns are pretty much maxed out and physics simply doesn't allow more.

This could result in interesting stalemates, a natural limit to the size of conflicts for example if it's possible to maintain a defensive sphere that can withstand the maximum level of abuse that a circle of attackers can provide - any weapons platform too far back being unable to increase the force applied. We might get technologically perfect civilizations effectively combined to bubbles of influence around their power sources.

What is possible is that at a certain level of tech we discover how to tap into the universal internet, aliens give us the rest of the answers to physics and philosophy then show us how to build VR gear so we can explore the cosmos in perfect VR and no one ever needs to build Dyson spheres or hyperwarp megastructures because we can do anything with a dark matter powered computanium smart phone.