u/HaikuDaiv

I think it's 53. That is by my calculation the highest possible roll for a Skill Check, but I may be missing something.
Here is my math.
Roll a Nat 20.
Be at Level 20, so a Proficiency bonus of +6. Expertise in the skill, so +12.
Ability score of bonus of +5.
20th level Bardic Inspiration, +12.
Guidance, max roll, +4.
Total of 53.

What am i missing? I am trying to limit to Kobold published material, because I am sure there are any number of third party classes that offer additional variations of Inspiration or similar bonuses.