There is a medium armor master feat that let's you boost your Medium armor DeX bonus to +3 and ignore disadvantage on stealth, but it isn't worth it for most classes.
With a rogue you will get 17 AC with light armor once you get your DEX to +5 without magic armor, which is the same AC as half plate(the highest medium armor,) so you are better off boosting your DEX.
The rogue also gains uncanny dodge at Lv 5, which let's them take half damage on an attack for a reaction, and evasion at lv 7, which let's them take half/no damage on DEX saves, which helps their tankiness.
They are also usually one of the few classes that get access to disengage and hide as bonus actions, which usually gives them an edge on survivability that other classes don't get.
You do have to be careful with that. I was considering getting light armor master for my wizard, and use the accompanying stat bonus to dexterity before I realized that would move me to +4 dexterity but the light armor would limit me to +3 - thus making me break even.
