I saw a TikTok idea where players have to build a level 10 character from scratch (straight build, no multiclassing, only starter gear, etc). After they are done, they get thrown into a ring to battle it out. I wanted to add to this idea by giving the players a time limit to build their character. I know it really depends on what class you build, your experience with a particular class, and whether you go with a website builder or just pencil and paper. So my overarching question is: How long would it take you? I feel like 20 minutes is good, but I'm not sure. 

Hard to do a 10th level spellcaster that fast unless you just use an autobuilder of some sort.

It would likely take me at least 20 minutes to build a non spellcaster to 10th level because of the feats/ASIs the class/race/background combos. Heck, it might take me almost that long to settle on a class & subclass sometimes. For a spellcaster? I’d need at least 30 minutes to pick spells.