If your claim of the WAVE having an empty dimm slot is correct then you could add a matching dimm and increase the memory amount to 16GB.
I don't see any specifications indicating a 128 GB SSD. The HD could be replaced with a hybrid HD or if you used an 2.5" to 3.5" adapter then you could install a SSD say in the range of 1-2 TB. The hybrid HD is probably your best option.
I don't see any relevant upgrade documents for the WAVE.
Your first consideration should be HP Sales or HP Support when considering memory replacement or upgrades. If you want to consider other manufacturers then the easiest way to avoid memory problems is to contact one of the major memory manufacturers. I am recommending that you try the memory tools from these manufacturers: Corsair, Kingston and Crucial. Once you have determined the dimms that you need, then contact sales or technical support to verify that you have selected the correct dimms. If you buy directly from the manufacturers, then they will stand behind their products. This WAVE is very new so HP is going to be your best option.
HP ENVY 6055, HP Deskjet 1112 HP Envy 17", i7-8550u,16GB, 512GB NVMe, 4K screen, Windows 10 x64 Custom PC - Z390, i7-9700K, 32GB, dual 512 GB NVMe, dual 512 SSDs, 4K screen, OC'd to 5 Ghz, NVIDIA 2080TI 11GB
Big Dave.....you sure missed the boat on this one.......please do your research before answering these tags, I've learned more about this product from people who claim not to be experts than that jiba ba yab you wrote.