You’re going to have to up your budget a bit. However, you can get a Thinkbook, which is exactly what you’re looking for - DIMM slot, upgradable NVME and USB-C charging. Only downside is that it comes with a fake (non-Zen4) 7th gen Ryzen processor. If you can wait for some time, the next 2024 ThinkPad E series may have DIMM slots without the soldered RAM nonsense.