It took for me around 3 months,with daily 2 SS convoys and 1 plunder (130 coupons daily),lvl 10 wishing tree (21 coupons daily),lvl 13 group wheel (arond 20-40 coupons daily,sometimes more XD).

If you can't do convoy,without being plundered,and have lower group wheel and tree,it could took you up to 5 months.

Also,try to avoid wheel events in general,Oasis is proven their RNG is not generous to most players.

thanks i actually fell for that recently now i learned not to. The reason i did it cause people got edo minato left and right within 1000 coups in the last event

persistent active daily.. for F2P

online for certain time.. u can get 10 coupons per day

group summon 40 coupons x 2 per week, 80 coupons per week

weekend mission, do the hardest puzzle.. u can get 10 coupons x 2, 20 coupons per week

i do 3 SS convoy per day.. so 120 coupons per day.. i dont do plunder

others like what Bogotor said

I use alt for plunder,to not harm other players income.

Also,from summon,it's 160 coupons per week,4x40.

And puzzles drop 2x20.

Well with the monthly cards it took me around 59 days for 25k coupons.