I am currently at 200 LP masters and has over 2m mastery points on jax.
I have this youtube guide posted pls check it out
https://youtu.be/lmcNoYsorYM
and pls follow my twitch if you like the content
https://twitch.tv/cxfytop

Ice born gaunlet allows you to stick on the champion you want to kill and unlock jax's full solokill potention as an autoattack based champion. After the jax rework, he does really good dmg from ult passive, you have more then enough to beat the enemy, the only thing holding him back is being kited, Iceborn gaunlet tech fixes this problem perfectly. The build is similar to the iceborn gaunlet viego from last season, now its good on JAX with the sheen hit. but do keep in mind that the build doesnt work vs ap champ since you always want to rush iceborn gaunlet. this build is really good vs these champs below assuming they arent running phase rush: Jayce, Nasus, Garen, Wukong, Irelia, Kled, Akshan, Quinn, Yone, Yasuo, Illaoi.
Another small tip on jax is that his passive attack speed scales up at level 4 7...etc, fight around the powerspike will allow you to win lane harder.
try to let the wave push towards you and run the enemy down with iceborn gaunlet slow.
IF enemy has phase rush, you can always go back to the regular sunder build since the runes are the same.
Good luck in the rift summonors.