When it comes to ranking job classes, it should be based on developing ERK metrics: Effort, Risk, Knowledge. This obviously would require many researchers to verify certain things: how many hours can the average person work in a field before needing a break, how many years of education before the average person can do a job effectively, and the frequency of death or injury from the task, and so on.

In any case, the income based on grades is for education - the idea being that students get paid for learning, and the more effective they are, the sooner they stop being students and enter the job market. The schools receive money for the grades students have, but have no part in the grading. It should be the state and federal government, through dedicated teams, that students are graded on tasks. Through the internet, it would be easy to transfer, archive, and grade copies of student work to these graders. This allows teachers to focus on teaching.

As to "If I do better than my peers, I want to be recognized for that. Otherwise, why would I put in the effort?"...honestly, I want this mindset to go the way of the Dodo. Your premise here is the very foundation of the rat race, because it creates excuses for individuals to be treated better than others in the workplace. If people do a job, it should be because they think it is neat, not so they could climb a social ladder.

When it comes to something like sex work, it can be based on whether you worked that day. If you did a lot of customers or just one, you get paid the same. While a company can certainly fire slacking workers, they also run a risk of an issue: worker votes. Workers, both fired and currently on staff, should be able to vote for leadership positions and benefits within a company. If workers don't get enough clients, the company won't make enough money to pay workers - so they are incentivized to find fair bosses who can dole out enough clients among the workers.

I would consider overtime and hazard pay to be the same issue. They can simply cause jobs to double in pay when in effect. Companies would try to avoid this when possible, so you would have the electric company trying to consistently maintain their infrastructure and services during regular hours. Night shifts can simply go to people who prefer them - after all, people have Rank 0 UBI. They are doing a job because they feel like doing so, and they will gravitate towards what feels most natural. Holidays are simply paid like any other day, regardless of whether anyone works.

The survival needs are a non-sequitur. "3 meal kits" means "3 meals a day", of which people can obtain the types that suit their dietary needs. It just means that these kits are standardized. Hotdog #1 (regular) and Hotdog #6 (Halel), and so forth. The important thing here is that government offers a baseline quality and availability for food that anyone can obtain.

As to labor shortages, that is a problem - but one not unique to UBI. The best solution in that case is to encourage students to enter the workforce, by offering a benefit to graduate from schooling. Which is why all jobs have at least double the income in a ranked system.

If I do better than my peers, I want to be recognized for that. Otherwise, why would I put in the effort?

About this, I will try to find it. But there is quite some research that shows productivity in simple jobs (think assembly line, or fruit picking) goes up in relation to reward. But complex an skilled jobs actually give diminishing returns quite soon with a higher reward, because with complex jobs most of the satisfaction comes from doing the job itself and excelling not the reward.