How to enjoy D4 longer than 2 weeks

Hello everyone. I started to play D4 after 2 years and at this moment im having a blast. But Im also afraid, coz I started 2 days ago and I already reached T6 with no big problems. And my gear is totally lame, paragon lvl 80 etc… will it get harder at higher Torments so I will have to optimize my gear before I push harder? Also how does the endgame look nowadays?
Maybe Im the problem coz I usually played grindy MMO so I also have no problem to grind in D4 for a lot of hours. But Im afraid with this tempo, in 2 weeks Ill be done and there wont be much space where to move.
How do u enjoy D4 for longer period of time? And when do u usually get bored and wait for new season?

Thanks for your opinions :))