But i don't see events that grant 3k coupons minimum to take part in it even for who doesn't pay unreasonable amounts of money.

Evidently you continue to think that anniversary has to be good for you guys only and not for your nonwhale playerbase.

I warmly suggest you to take a look at what other games like soccer spirits, knights chronicles, sid story or seven knights do for their anniversaries to try to learn a bit about what means to be f2p friendly while you also earn money.