I don't have a channel or server for advertising, but YouTuber @Fury-ju6md helped me a lot

I will be glad if after reading you watch his videos, he often and a lot publishes walkthroughs with comments, which helped me to understand the game more deeply

potential +40
Tactics
White +25
blue + 30
purple +35
gold +40
double +80
+20% HP +20
+20% MP +20
buffs/debuffs +0

How does rank affects your evotype efficiency - there is no linear relationship, but
potential boosts all damage of your character (not tactics) by 20%
Tactics and HP/MP boosts are fully preserved
HP that you pay in Black market is fully returned
All dmg boosts that comes from text - are temprorary and would by errased after run

How does it works?
Covenant significantly reduced your ground damage and increased your air skill dmg - its +0 rank point and +0 evotype damage after your run
Black market take 150% hp and gives 25% hp for perfect clear, you saves all your collected hp and get 150% hp back
Black market take 90% hp and gives 15% attack/skill dmg for perfect clear. After run you would only get 90% hp back

How does rank affects your evotype legacy skill? Nohow

Why should I care about this, if it does not affect further attempts?
There 2 more game modes, mind trial that gives you money and boss rush that upgrades evotypes legacy skill (make it stronger and gives you 1 more variant to choose).
I won't give spoilers for upgraded skills, but you should upgrade at least Hibiki and Ragna

You have 5 trigger slots, each have tactic slot, if you cant apply 1 tactic in 2 slots (ring of fire goes in skill OR legacy, not both)
Each tactics give you moderate amount of extra damage:
Fire: give dmg per second for 5 seconds
Ice: less dmg, but slows
Blades: summons blades, normal dmg immediately
Shadow: normal dmg after 2 seconds
lightning: normal dmg, that divided by enemies
poison: huge dmg after 5-10 seconds
light: good damage with conditions for activation, also allows you to avoid damage from enemies

+1 rarity gives tactic +10-20% dmg
II and III step tactic boosts damage of original one by 60-100%
after you take III level tactic you could get double tactic
In long term there no big difference in common tactics, the main goal is to peak right one to get few doubles
How should I choose right tactics?
There no big deal in 90% times, but you shoud remember:

Tactic rooms spawns randomly
If you have no trigger slot for new type of tactic, room of new type wouldnt spawns anymore

If you whant to get more potentials/shops/sortio rooms - you should peak tactics of 1 or 2 types
How to do this? Save evotypes with 2 different lvl 1 tacts of same type and play 5-0 (fire/light) or 4-1 scheme (blade+poison/light + ice)
90% of games you wouldn't get more than 3 double tactics, so 5 Doubles is not your main goal

How should I choose evotype for legacy?
Skills are mostly "deal X dmg", try each and decide, which one is more comfortable to you
Most significant - Ragna (heals you), Hakumen (blocks 1 hit), Taokaka II skill (surprise), Noel II (surprise)

Passive is more different
Most significant - Jin (slows the world on dodge), A-No-11 (restore MP), Icey (kill robots faster)

Dmg or other effects don't affected by rank - so you coud farm low rank evotypes with good tactics and passives

Conclusions:
Farm few Evotypes with 2 lvl 1 tactics of same type
Farm few Evotypes with lvl 1 tactic + Double tactics for same trigger slot

Prioritize chars you don't love, but with good passive / active you love:
Ragna
Jin Kisaragi
Mai
Taokaka (after boss rush)
Hibiki (after boss rush)
Noel (after boss rush)

You should gitgud first - be sure you wouldn't die in next room, before blind pick it, feel free to choose more save options.

General line:
Black market
Potential
Shop if you have 500+ CP
advanced battle
Tactics of type that you have/want
CP
Covenant
Sortio
Shop if you have 200+ CP
Rest
any other trash

Why shop and black market so higt?
It got good options, BM could give you 999 CP, HP boost, 5 random tactics. Shop give you 1-3 Potential based on your luck and CP amount
Why covenant is so low? It has only few good options and debuff could ruin your run
Good options: +2 free shop refresh (so you get 4 total), randomly doubles sortio prizes (read like get x2-x5 of base reward)
Why sortio is so low? It gives you stats, CP or potential refresh, nothing of this is your final goal

There 3 main groups:
Get extra dmg
choose more stable
+ attack/skill dmg
+ attack dmg after skill
+ dmg for killstreak

Get extra CP or lower price
+ Shop discount
+ init dmg
+ extra potential refreshes

Get more safety or stats
+hp recovery after each room
+hp recovery after perfect clear
+1 review
+ hp
+ mp

Another options, I personaly don't use, that many people like:
Mixture Count + Mixture Healing (extra 400-600 %hp healing per game)
Not Dead Yet + Defensive Combo (extra life and 10 seconds of i-frames let you finish any boss fight)

As you see - I don't know how to add images, after I find out - next step is guides like:
"best tactics builds"
"best potentials for each evotype"
"all in-game achievements" (with "how to beat every boss" part)