Playing Hearthstone after ~9 years

As the title says - i haven´t played for ages. What did I miss? What should I play? I tried playing arena because for that I don´t need any of the new cards and that was quite fun that´s why i want to continue playing HS.

I´m not sure about playing ranked because I don´t have any of the new cards, I see that quests are a thing now.

Please tell me what I need to know now :) The last time I played forsen, amaz, kripp, trumpSC were a big thing lol.