Player hates death saves.

As everyone have already said, the problem here is not with death saving throws per se. Players have to avoid the situation, that can lead their characters to hitting 0 hp. 1) You need to be sure, that they know how healing and stabilization work in D&D. Healer's kit, Spare the dying cantrip (it's not that effective, though), Medicine check, and it doesn't have to be Wisdom (Medicine) check, ask your players how they want to bring their party member's poor soul back to the body. For example, your player's character can wield some knowledge of anatomy from their backstory, so if they say: "I'll try to stop the pulsing bleeding by pressing slightly above the wound", I would ask them to pass Intelligence (Medicine) check instead of Wisdom. If they have Medicine skill, their proficiency bonus adds up to their characteristics modificator and result of a d20 roll. Don't forget about basic healing spells either. 2) If the player wants to play Rogue class, they have to investigate the area before the battle starts or at the very start of the combat. It's crucial for this class to get benefits from their position in order to stay alive and be effective. 3) Maybe it's better to let your players start with 3 lvl characters so that it would be a little harder to kill them. Lvl 1 characters are way too close to commoners compared to higher levels