I had the same trouble last week. I made the Odogaron set and upgraded each piece 3 or 4 times. Made it so I didn’t get one-shot by his dive.
Edit: I just made the set with the most base defense that was easy to get for me. Figured the raw defense would help, and it definitely did.
Edit 2: Also something I didn’t know about until a couple days ago, that I hadn’t seen mentioned here. Maybe I missed it though. The trader guy in base camp sells a Powercharm and an Armorcharm. They give flat Attack and Armor boosts just from sitting in your inventory. You can upgrade them once, by combining with a beetlejuice talon and then rebuy the original version.