Lost index - what should i do

i have a new web https://77win.fund/ when i open google bot to crawl, in 2 week, i have >60 link indexed, i got position 2 in key: 77win but then it down to 20 - 30 - N/A my link indexed lost too > 50 > 40 what wrong? what i need to do? audit content or backlink ... or do more social backlink, forum, ... tell me anything else that u know it good thank you so much!