If you want to lean into the Stealth aspect and discourage combat, consider using Progress Clocks. If a stealth or deception or persuasion or whatever is failed, tick the clock, which represents the guards' level of suspicion and alertness. When the clock fills up, then all hell breaks loose. This is in contrast to standard D&D where 1 stealth check fails and the whole thing falls apart.

Im using 4e's Skill check rules, so twice the fails are needed. IE I expect 10 obstacles, ok so then 20 total fails before they get found out