Hello,
I guess you aren't playing diablo since a long time?
Basically, all your items can be ancient.
It mean their stats will be higher.
(let's talk about a chest, you can have dexte from 450 up to 600. The same chest, ancient, will be 550 up to 750)
(it's an example, no idea about real value)
Also, you will need to deal with mariam, and roll your stats.
(I do'nt know if you already did)
For each stuff, you can reroll 1 single stats, to get another.
And on monk, for example, you will roll life/hit for critical chance.
And finally, don't forget your gems.
(basic & legendary)
Anyways, if you can post here your profil, using d3planner (import your hero stuff), we'll be able to help you and give you more accurate answers.
And to answer to your question, yes, with ancient items, you will be able to cleat T10
OR GR 49 in approx 4-5min easily.
(Note that T10 and GR49 aren't the same

)