I don't think we can continue simply tweaking the transformer architecture to achieve meaningful gains. We will need new architectures, hopefully ones that more closely align with biological intelligence.
In theory, the simplest way to real superhuman AGI would be to start by modeling a real human brain as a physical system at the neural level; a real neural network. What the AI community calls "neural networks" are only very loose approximations of biological neural networks. Real neurons are subject to complex interactions between many different neurotransmitters and neuromodulators and they grow and shift in ways that look nothing like backpropagation. There already exist decently accurate physical models for single neurons, but accurately modeling even C. elegans (as part of the OpenWorm project) is still a way's off. Modeling a full human brain may not be possible within our lifetime, but I also wouldn't rule that out.
And once we can accurately model a real human brain, we can speed it up and make it bigger and apply evolutionary processes to it much faster than natural evolution. To me, that's still the only plausible path to real AGI, and we're really not even close.