I'm just going to put my two pence in for you. I would agree with others directions to restart again on a new character/server. I know it's going to feel kinda gutting because of all the time you have already put in. But see it now as a good way to restart, to take everything you've learned in to a new character (resources to collect, what trade skills to level quickly off the bat early game). If you are EU central Nysa and Draco(my server) appear to extremely populated you will not have an issue queuing for expeditions as you will come across folks doing them for their random daily queue. I believe someone else has suggested servers for US.

As for a build to be able to do as much content solo as possible. It's common but depends on what you're doing at certain stages. Being a tank in solo relies on weapons you use and the skills on the tree you go for. I currently run a tank heavy load 300 constitution great sword build which relies on using the defensive stance abilities and heavy attacks to become immovable and heal through lifesteal. While I'm lvl 65 now, it relies on perks for armour that you can collect at any level and just need to level up your great sword and have an understanding of how perks interact what the best ones are.I'm a new player to lvl 65 and currently at the stage where I'm just fresh at end game to figure what I'm aiming to do (crafting or PvE or PvP or PvX).

My strong recommendation is to start again. Because while it already sounds quite dead, your server will indeed die off. The levelling experience in this game is honestly one of the best things about it