Is Unranked Skill Based R6?

Casual and unranked, yes. It's all got hidden MMR so that the more you play of it the more you're matched with other players of your skill.

Is unranked skill based matchmaking?

Unrated is an alternate label for unranked gameplay in Valorant. There will be skill based matchmaking in unrated :). Not beating around the bush as many devs have in the past when it comes to SBMM, he outright confirmed unranked playlists will, in fact, be influenced by skill.

Is unranked good r6?

From my current experience, I've found that the Unranked playlist is a good alternative for people who want to play Ranked, but are afraid of losing their ranks. It's a good environment where you can test strats with teams, or get used to the more competitive way of playing siege.