Best Combo

oder die Methode

1. Gedenkmünze von Glisch
2. Sprache der Fogan
3. Donats Testament
4. Freharau und Erleuchtung
5. Köstliches Wasser

6. Verbranntes Kultistendokument

oder

6. Ceasars Geheime Methode

1. Parts Delivery to the Extraction Mill
2. Fogan Language
3. Ceasar's Secret Method
4. Donatt's Will
5. Glish Commemorative Coin
6. Freharau's Scar

Interest < 35
Favor < 30

If interest and favor is above this, just try again.

Easy ~50 amity per roll.

Data of knowledge at NPCs Interest Level at 40 (mid-range) and Favor at 20 (low-range). Sorted in descending Interest Level order.
Note that Interest Levels, Favor ranges and effects change after game updates .
I made this for myself (on spreadsheets ofc) and though why not to share (after doing fast regex replace).

name ( interest [spark rate] favor min~favor max [actual favor min~actual favor max] effect )
Naga Sculpture ( 4 [10%] 43~53 [23~33] )
Calpheon Apprentice Priest ( 11 [28%] 31~40 [11~20] After 3 +1 Interest for 4 )
Cave That Nobody Knows ( 11 [28%] 40~46 [20~26] )
Black Crystal Pouch ( 17 [43%] 45~47 [25~27] )
Donatt and Mudsters ( 22 [55%] 30~39 [10~19] )
Disappearing Maiden ( 28 [70%] 25~28 [5~8] After 3 +4 Interest for 2 )
Secret Place ( 30 [75%] 20~29 [0~9] After 5 +3 Interest for 4 )
Fogan Language ( 30 [75%] 35~44 [15~24] )
Ceasar's Secret Method ( 31 [78%] 34~40 [14~20] )
Freharau's Scar ( 32 [80%] 33~38 [13~18] )
Extraction Mill Laborer ( 32 [80%] 35~40 [15~20] )
Donatt's Will ( 32 [80%] 37~45 [17~25] )
Glish Commemorative Coin ( 32 [80%] 37~42 [17~22] )
Parts Delivery to the Extraction Mill ( 33 [83%] 31~37 [11~17] )
Cultist's Burned Document ( 41 [103%] 4~7 [0~0] After 4 +3 Interest for 1 )
Freharau and Enlightment ( 42 [105%] 3~8 [0~0] After 3 +3 Interest for 1 )
Delicious Water ( 42 [105%] 4~6 [0~0] After 4 +3 Interest for 4 )
Water Purifying Facility ( 43 [108%] 4~9 [0~0] After 4 + 4 Interest for 1 )
Fogan Test Subject ( 45 [113%] 3~10 [0~0] After 5 +4 Favor for 2 )

For favor gain I would suggest to use 2 high Interest Level (preferably with some Favor), then 1 high Favor (low Interest), 1 high interest and lastly 2 high Favor (low Interest).
Don't forget to re-roll for low-enough Favor and Interest Level for requirement to be passable.
Be flexible, do what mini-game requires.
Don't blindly follow outdated builds, see what those builds do.

Not gonna research for best builds since it takes a lot of time to make for all scenarios. And even regular maintenance of BDO changes knowledges quite a lot.

Glish Commemorative Coin
Donatts Will
Fogan Language
Naga Sculpture
Black Crystal Pouch
Cave that nobody knows

Interest and favor highly varies, so try rolling low ones. Also, this combo only works well with low enough interest values. But if you have that, it's nice.

1# Kazı Alanına Parça Teslimatı
2# Fogan Dili
3# Ceasar'ın Gizli Yöntemi
4# Donatt'ın İsteği
5# Glish Hatıra Parası
6# Freharu'nun Yarası

Em português:

Moeda comemorativa de Glish
Idioma fogan
Donzela Desaparecida
Freharau e Esclarecimento
Água Deliciosa
Documento Queimado do sectário