Raiding/Fractals/Strikes might be tough to start as a group of 2-3, but you can look for learning groups until you feel confident enough to just join randoms.

I learned to do fractals from following guild members back in the day, and now that I'm coming back after a 6 year hiatus, I'm just doing tier 2 or tier 3 dailies and enjoying them again. Strikes and raids require a bit more work, but they're quite doable as long as you have a good teacher and can manage your mechanics on top of your role.

WvW and PvP are modes you could look into. Also chasing legendaries is a great long term goal.

imo you can totally get into raids and fractals with 2-3 people.

For fractals, you're just 2 shy of a full party. Throw a post up on LFG and it'll be filled in 5 minutes easy.

For raids, have your friends learn healers or supports and you'll quickly fill the remaining spots with "hi dps"-ers. Or honestly just having a 3/10 LFG post up will get some gamers filled in regardless of what you play. In my experience it's the 1/10 groups that are the slowest to get started. Just make sure you post for the right roles ("w1 full clear lf adps,qdps" for example) so people know what the group needs.