how POE 2 gems levels ?

From the interviews that I have seen it seems that the gems have stat requirements of like certain dex or others. I do love the idea of uncut gems leveling skills then I wonder when I find an upgrade for a gem I love but when upgrading to the level will it lock the skill level to the highest I can use now and level it up passively as attributes increase allowing me to not use uncut gems on that skill. If I am not wrong you can trade the uncut gems to other players (comment for correction on this) what would happen when you just started a new character and give him all level 20 gems you are going to use ?
what are your thoughts on this I wonder.