13-14" Lenovo Ideapad, Thinkpad, HP Elitebook, MSI and Dell Latitude all have laptops with 2 SODIMM slot. The real reason behind soldered LPDDR4x-4266 memory is for Tiger-Lake-U performance boost, not because of the chassis' physical limitation. A good example is LG Gram series transitioning to soldered memory this year with 11th gen, despite all the backlash.
HP sets the Envy 13's (iGPU) TDP up to 30W max, so I'm sure the more power-efficient Ryzen 35W chips wouldn't be a problem. Lenovo and Tongfang are two manufacturers working on 35-45 AMD chips in smaller, lighter ultrabooks, so I'm sure HP is perfectly capable if they tried, since they already have the OMEN gaming laptops and ZBook workstations that were without serious thermal issues in 2020.
Also, the 1650 Ti Max-Q in the Envy 14 should be 35W TDP variant, probably even more power limited as HP did with the previous Spectre x360 15s.
So really, HP has no excuse here for not providing us consumers with an AMD option with better performance, efficiency, serviceability at a lower price.