Every current guide would tell you the same things in this particular order that I’ll improvise for you:
Stage 1: Halidom sets
These are the “better than nothing” sets you should have in order to enter Interdimensional Rift due to its Exorcism requirements. lvl80 sets are the bare minimum and can still help you reach the end of Scenario.
Stage 2: OV sets and the Legendary sets “spectrum.”
Get all this stuff from Interdimensional Rift. You need OV sets (among other things) to increase the level of your buff. Never use them for damage; they’re gimmicky at best these days. Crusaders need certain OV sets for the bare minimum increase in their buff skills. I call Legendaries a spectrum cuz there’s various combinations you can choose, really. Either a 6pc set + 3pc mini-set for accessories, or a 6pc set + Area Legendary accessories from Central Park. Either way, you need a Requiem/Liberation/Terra Reconstruction weapon by this point. This is all the bare minimum to enter Anton Raid and especially Echon.
Stage 3: Echon + Crafted Epic + Epics
This is pretty much a spectrum all on its own. If you have Leg sets and just got a crafted Epic weapon (with bonus effects), you can at least keep up with a Raid party. But an Echon set can carry you pretty far if you know how creating a set works. Nevertheless, if the character you’re gearing is the one you wish to invest DI’s on, get some epics. You can always use them as off-slots to complement an Echon set, preferably with Atk Dmg, Crit Dmg, and Skill Dmg. I can’t answer for whether they can take you to Luke Raid though.
Stage 4: Epics
Regardless of which route you take, Epics are the logical conclusion to gear progression. For now, at least. Anton Raid has good accessories you can grind for and they compensate for whatever Smash modifier you don’t have. Do yourself a favor and take what you can get and use them however you can. Choosing which lvl90 set to farm for is fine and all, but RNG won’t give a shit what you want. If you’re 3/5 or 4/5 in a set, chances are it’s the set you’ll end up using for a while. Learn how to farm DI’s, use all content that awards Epics in some capacity, and consult with veterans on your builds.
You can check a guide like this one for more details. The Ultimate Guide to Gear