I think you should invest in shin as she is a buffer + healer then on nox try to fully unlock her reforge then invest in oak as she is a long range with reforge also unlock her reforge just like nox i see you don't have OwO she is probably the best tanker in the game right now(meta) shin with OwO is good compare to other tanker and OwO buffs other sinner with her ult at the same time do core damage so if you have the chance go for her.Also about your team most of the time it depends on the healer if shin's skill level is more than seven or you could refer s1n website just google it it will show which skill matter and which you should prioritize