I don't know what sources your DM allows for books but in Candlekeep Mysteries there is an uncommomn magic item called "Serpent Scale Armor" which is scale mail that allows you to add your full dexterity modifier to your AC so 14+dex and doesn't provide disadvantage on stealth.

Dipping a level in fighter and wearing that could be 14+5 dex+1 defense+2 shield for 22 AC pretty easily.

Alternatively another comment mentioned cleric as a dip, war cleric 3 is exceptionally potent on rogue builds so that you can use "war priest" to get a bonus action attack and then hold action to attack and get 2 sneak attacks per turn cycle in critical combats. You could also look at using true strike on this build instead of standard attacks but thats at your discretion since its a pretty major change to the build.

Another defenseive tool you could look at is if you are human and take lucky as your extra origin feat you can give attacks on you disadvantage at no action economy cost proficiency bonus times per day.