I did a int/dex build as well and loved it. I used the Demi Human Queens Staff and Moonveil Katana upgraded to the max, I may have switched the staff at some point but that took me very far. You should also look into the FP physik tears, especially the Cerulean Hidden Tear + Magic Shrouding Cracked Tear which makes it so easy to blast off some big spells for free and high damage. I especially recommend using it with the Comet Azur to wreck bosses right off the bat.
Interestingly I’d say Elden Ring is the most forgiving when it came to the “death penalty” you mention compared to all the other titles. There were far more rest points and things were so much more interconnected so you can stroll through/around most of the enemies to get back to where you died. Not always but a lot of times.
Also I found that really using your summons (especially mimic!) really helped with the difficulty. Also using magic makes life way easier. A lot of people just tend to go for the pure melee build which is making life really hard for yourself.