C0R1 > C6R1 power increase

I've currently got a C0R1 Chasca and a few more R1s [Mav, Varka, Nefer, Skirk, Xilonen, Furina (accidental)], and a C1 Zibai (early). I've been playing for a year and a half (Welkin+BP) and am at a point where I've got all my elements sorted for IT and can 36 the Abyss regularly, but Stygian is a hit or miss obviously, and I'd like to move into cons. So far, Chasca and Varka are my favorite characters, but I like quite a few, but these two are the only two I've contemplated swiping for. I understand that C2R1 is typically the best stopping point for most characters so I'm curious about two things I was hoping some whales could clarify:

1. What's the difference between C0R1, C2R1, C6R1, and C6R5, both in terms of raw damage/flexibility, but also in terms of fun and play style? I've seen shorter charge combos and was curious how she plays and if it's more interesting than just holding CA until she gets to 5 shells. Did either of these stopping points feel "worth it" to you? C0R1 was 100% worth it for me for the exploration and flexibility alone. Also, what are some of her better (non-Mavuika or other pure-DPS or Binnefa wheelchair obviously) teams past C2, considering she can add Anemo/Dendro/Geo/Double-Pyro?

2. How many pulls/primos/dollars should I expect to spend to go from C0 to C2 and C6? I'll have a bit over 165 pulls in the bank by the time the next patch arrives, but I do want a copy of Linnea for my Zibai team, so happy to spend on Chasca. Just curious what to "expect".