Do I loose everything in PO2?

PoE 2 is nothing more, nothing less than PoE patch 4.0. Patch 3.0 brought massive changes to the game, and 4.0 brings even more. There will be permanent changes, but things like Standard characters and stash, MTX, and HOs will for the most part remain untouched.

There will be new lore in the form of new Acts, but rather than adding to the existing 10, you pick which story to level through. There will only be 1 Atlas, and it doesn't matter which set you go though. There will be 16 new Ascendencies but all 32 will be eligible for either set of Acts.

Sockets will be removed from gear and rolled into a separate window. You will be able to have 9 sockets (some gear will offer additional sockets), and each socket can roll up to 6 links. Jeweller Orbs are being removed from the game and will be converted to something comparable. Fusings will roll number of sockets that are always linked.

Each 6L will only have 1 available active skill, but some will allow for multiple active skills to be placed. Enlighten for example, will be the active skill and allow auras to be socketed. You will then activate Enlighten to trigger all auras at once. CWDT an other similar existing gems will function in a similar manner, and there will be new gems like this. For the life of me I cannot recall what they called these.