20 usually is much better to farm, because usually you can do it on auto while you (or at last me) have do it manually on 21

Plus there are some factions where I would never, ever do 21 again (e.g. Knight Revenant)

I checked the drop rates, and if they are accurate, there is a slightly advantage to farming 21 over 20 in terms of glyph quality and materials. However, it was quite small, and 21 is generally considerably harder/slower. If you can auto 21 in a reasonable time, do it, but if not it's probably not worth the extra time and effort.

During CvC it is worth considering however, since it's twice the CvC points to beat 21 over 20.

I do 21 because i think (but do not know) that there is a better chance of a top glyph

King  N.  Is  correct.

First  Half  of  what  EGNIT  said  isn't true.

Glyph  Drop  Rates  for  21  &  20  are  even  -  Players  did  test  on  those  2  Stages.

Second  Half  of  what  EGNIT  said  is  true.

Most  farm  20  over  21  due  to  time  &  some  Faction  Bosses  are  hard  to  Auto.

Third  Half  of  what  EGNIT  said  is  true.

C  vs.  C  Stage  21  is  better  because it  gives  more  points.

One  Thing  I  will  add  is  I  found  Stage  16  to  be  very  good during  C  vs.  C.

During  C  vs.  C,  the  following score  is  given

-  Stage  21  gives 1k  points

-  Stage  20  to  16  gives  500  points

If  you  can  beat  Stage  21,  It  can  be  worth  it  to  your  team  score  during  CVC.

If  you  can't  beat  Stage  21,  You  have  to  consider what  Stage  to  get  points  from.

Most  people would  go  to  Stage  20,  but  Stage  16  gives  same  points  as  20.

It  could  be  worth  it  to  do  Stage  16

Good info. Thanks. 

For reference, this was my source: https://ayumilove.net/files/games/raid_shadow_legends/guide/droprate/FactionWar_LootTable_DropRates.jpg

I remembered wrong, the glyps have the same chances. Materials is slightly better though. Assuming of course that the table is accurate. The claims are not sourced from what I can tell.