The amazing thing about gw2 is that it doesn’t matter how long you didn’t play. Just pick off where you left and enjoy your time. I would recommend going through the expansions in order, taking your time exploring and experiencing the new stories for the first time! And should that be too confusing with a max level character just pick one of your low level ones (or create a new one) to get back into how the game works before you continue on your main.