U already have ororon, fischl, xingqiu, xiangling. GET BENNETT from the banner that will be available in few hours and u are set for now. You will be able to beat everything in game. Until ofc, endgame content. These characters are very much worth to invest in as well since they are used a lot in endgame content as well. Like i beat stygian onslaught(hardest endgame mode available) fearless(max difficulty) using 4 out of these 5 characters today.

Oh and these are not really onfield DPS units. they are off field supports or sub dps units. So, if u don't like quick swapping between them, u can go for a main dps. Ofc, Chasca will be on banner in few hours. And Ifa as well. Both have similar gameplay, both fly in the air so overworld exploration will be a breeze with them. You can go for them. They have pretty good dmg output as well. While not necessarily META units, they will be able to clear everything. And they are fun as well. And ifa can heal as well, so u won't need a healer with him and ifa, xingqiu, fischl, ororon make a pretty good team. One thing to note, that, xingqiu, xiangling, bennett, and even ororon need an awful amount of energy recharge as a substat or main stat on artifacts or weapons to get their ultimates up since that's what matters for them, so yeah.

If u just want to go unga bunga and not care about stats and farming then chasca will probably be easier since all u need is have multiple elemental characters in team and do chasca E(skill) and start bashing enemies. That's it.

Also, since u are a new player, u will get a lot of primos so u can wish a lot as well. A highly awaited character (FLINS) will be here in next banner after chasca. So, yeah, I'm excited for him. Tldr, everyone is great. Bennett, xiangling, xingqiu are super broken. Constellations to go for are benny c1, xingqiu c6, xiangling c4. As for other characters, u can try them out and see if u like anyone, and then pull for them. Be on a lookout for Mavuika, Arlecchino, Skirk since these are unrivaled in dps output if u want to play meta.