Hi. Welcome to the game first off. It's hard sometimes for veterans to remember what it's like to be totally new to the game and feeling really confused about what is happening, so I can certainly sympathize with what you expressed.
First off, if you are not aware of this, there is an action camera option in GW2. Turn it on in your settings under camera. You will find you can target what you have your crosshair on just as in ESO, so no need to tab target. It is not the best way to play if you are in PvP mode, but it's pretty good in PvE so try it out.
Second, if particular aspects of the Mesmer class appealed to you when you chose it, then those things may be important factors in choosing your elite spec. later. Mesmers, by definition are not straightforward classes like Warriors or Rangers, as they have a unique way of both fighting and defending themselves against enemies which go beyond just the weapon skills and effects, as you probably already have seen.
Traditionally, when the Chronomancer spec was introduced it was a highly effective spec for tanking in group content, but over the years it has been changed a lot so it has dropped out of top tier favour compared to other support specs but it is still pretty good as support. If you like being more of a supportive player to your team it's highly enjoyable and a very solid choice. The condition variant can also provide a lot of dps in addition to quickness. You can play it as straight up power DPS as well but it does take some time to get used to it unique use of wells and longer rotation.
Mirage is by far one of the more impactful specs in the game for damage dealers, despite opinions to the contrary.... part of why it has been seeing many recent changes is because there has been some concern from the devs that it was over-performing in it's role as dps and as alac dps. It just one of those specs with both a high skill floor and ceiling, so the better you get at playing, the stronger it will perform for you. Personally, I have been playing Mesmer since beta and Mirage is by far my favourite spec, so know I am probably a little biased on this. While it's true recent changes and the ones coming up will bring us down a notch or two again, it still remains to be seen by how much. Mirage offers high damage, fast play style, and good defenses so you can be incredibly independent and tackle just about any enemy with a lot of confidence and effect.
Virtuoso, the pink flying dagger thingy aside..., has some interesting play in that your daggers replace your traditional illusions/phantasms on shatter, so in some ways it feels a little antithetical to the entire concept of a Mesmer. It was introduced in the latest expansion, and so it is pretty popular with many players especially ones who are new to Mesmer. It has a much lower skill floor than Condition Mirage or Power Chronomancer, so it is very beginner friendly. But it does take some solid practice to bring up your mastery of the spec which can make it a little deceiving in the beginning. It has effective builds for both power and condition, so either would be a nice one to try out.
This all said, if you feel you got to 80 too quickly, which is understandable, there is nothing pushing you to do/choose elite specs now. You can always focus on doing things like map completion and mastery points round the base game, before jumping in to expansion zones. They will always be there so you don't need to hurry unless you want to. Having more confidence in your class as a whole is important so read all your tool tips, not just on your skills and weapons but also on your trait lines so you are clear on how they synergize together and why.
Feeling like your understanding of the core class is on more solid ground will help you decide which things you want to try first in the elite specs. Optimizing can come once you are clear on why you are doing it -- just throwing on a build from SnowCrows or Metabattle without clearly seeing why it is set up that way will not help you play any better. Practice is what will give you that understanding, and being in real combat not just on a golem As is, they are all pretty cool specs for different reasons, so just have fun with it and see which feels best to you. Cheers! 😊💜