Player returning

Hi, i have played a lot of pre renewal ragnarok over the past 15 years, and the last time i play was 3 years ago in a low rate server, coming back now in transcendence and i want to know a few things from the most experienced players.

I think i want to do a crit sin, is a viable job? What are the best equipments right now? I think i will spend a few dollars on the game, because i dont want to farm zeny, just enjoy the class i play. (like in old servers, i always created a rogue farm, and start farming).

With like 50kk i can get most equipments i need for a crit sin?

And the server is in a good state of healthy? Because from what i'm seeing in prontera, there is plenty of people.