How do i most easily get heroic invitations? i gotta get my second hyper fr

[glacial tree]

i dont have heroic invitations and idk which dungeon to grind

[vital basalt]

Secret dungeons drop gold medals, exchange them with Ariel

[livid robin]

Heroic tickets can be bought from board, obtained from Elrianode dungeons, and El Rewards trading from Ariel

I think you can also get them from Drabaki dungeon too idk