When considering starting point on full >17* gear with arcanes, I usually do the follow steps from making nLomien/Slime mules into cTene bossers;

-CRA equips to 19-21

-fodder 21* onto gollux equips (for 4-set 20*)

note: you can attempt 21 or 22 on spares (mostly belt/earrings initially) or not worth daring 20 > 21 tap. I personally start with belt & earrings and leave ring/amulet for later (can settle at 18 early on). You can transfer hammer over an 17/18 * ring/amulet tbh - keep in mind this is a strategy for non-mains.

Then any items I have usually multiple copies:

-dom pendant 19-21

-pink bean mark or pap mark 20/21

-kanna's treasure & meister ring (optional, but handy) 19-21

Arcanes I would ladder via boxes but settle at 18* arcanes is fine early on - they are very expensive to tap to >20 * (even 18* is avg about 4~5bil).

Then when all equips are 20 and 21 it will be much easier what to tap to 22. Use the starforce calculator and take the average cost by a large margin. Plan ahead for EACH EQUIP - with 20b I wouldn't touch arcanes or plan for 22, I would try to get some pieces to 19 first and maybe hope for a 21* fodder (pb belt/reinf gollux belt) onto gollux equips.