I, for one, would start with getting the hang of some builds. snowcrows.com has builds for high end gameplay (which I recommend) and open world. Many HoT and PoF elite specs are still meta. If you buy the Icebrood Saga story steps, you get access to the IBS strikes, which are a good mid-point between open-world triviality and higher-end content.

gw2efficiency.com is a handy website that allows you to gain an overview over your account, as well as offering crafting support, allowing you see what materials you ate missing to craft an item.

I took a years-long hiatus after HoT, briefly returning for PoF and I only really go back into the game after the Icebrood Saga already concluded. I wanted to complete legendaries, since after the introduction of the legendary wardrobe, you can equip any legendary on all your characters now. I also got into instanced content. First fractals, the raids, then strikes. I now am fully kitted out with legendaries and run all raids and strikes with CMs (- ToF CM) weekly.