Paragon is a pure single target dps specc not a good aoe or solo specc.
Solo i recommend warlord/champion hybrid here is a good guide on it.
At 60 with some decent gear you can solo in riftblade. Also riftblade is a great specc for groups as it can do some decent aoe damage, good single target damage, and still do some dps from ranged(not as much as in melee or tempest).
When soloing you want a specc with self heals in it otherwise you will struggle in storm legion.
In groups you can use a number of different speccs paragon, tempest, riftblade, champion, warlord. All of them good at different things.