I'd say it is, though interacting with other players do make the game better. You can do the main storyline together with friends, but only the party leader can complete the missions - so if playing with group of friends you need to repeat every quest with everyone which is not optimal. That said you can easily complete all of the missions solo: only the really end game missions are so hard that they are easier to complete with others.

There's tons of content where all the people on the server contribute together, but you don't need to communicate or coordinate. There's some content that are meant to be done with group, but you don't need to communicate too much on those either: just jump into a random party, have fun and jump out of the party.

And of course you can also just roam around the map with friends or visit the houses of randoms and that's neat too.

Usually when I am playing solo, I just jump into a random party to get some perk bonuses and do whatever I need to do, then jump into another party that's build around some objective and do that, then continue playing solo and so forth.

Like I said, the community is SUPER friendly and non-toxic, so you can engage with other players or ignore them as much as you want to without one anyone grieving.