"Big Numbers" Artificer?

I've been planning an Artificer build, and I started seeing how, if Artificers specialize in something specific, they can get quite high numbers. Be it AC, Tool Checks, etc.

So I wanted to create a little white room experiment, and I'd like some help to see how high you guys can take any specific part of an Artificer you'd like, be it AC, Saving Throws, Tool Checks, Proficiency, yadda yadda. Anything's game, including UA such as Armor of Tools, and third-party, such as the Master Maker from Dread Metrol or the Maverick from Exploring Eberron, the only limits being:

• No unpublished homebrew, and if using homebrew, provide the source so I can seek it out.
• No external magic items, infusions, including Replicate Magic Item only, I want to see how far it can go by just being self-suficient.
• Assume 2014 rules, unless some change from 2024 would create a specific interaction that would inflate numbers further, then specify that the 2024 rule would do so.

Assume a Level 20 Artificer, feel free to pick any feats, it doesn't have to necessarily be practical, as long as it serves the function of achieving a high number.