Create the most 'stressful' tennis match ever!

What you are missing is called "competitive balance" in the economic literature. You need a set of rules to assure it, otherwise, you will have a major leaguer play a t-ball player.

Since players are randomly generated, you need a rule system that begins to systematically sort players of similar rank.

There are two distinct issues here. The first surrounds the mean, the second the variance. Two t-ball players are unlikely to meet a stress condition because their natural variance is high. Two professional players are likely to face the stress conditions you are seeking because the mean rank will be highly similar and the variability will be very small.

Your rules do not seem to allow learning. Random systems will have grave difficulties in creating a stress system because it would be like playing competitive Roulette. While 90% of the scenarios have to have between 1000 and 1500 points, you could play low-level qualifying matches with few points. You could use something similar to a Swiss System tournament with an Elo system to rank. This is prebuilt so you can adapt it to your needs.

If sorting is not allowed, then handicapping is your alternative. This takes away any advantage. If you want to maximize stress, then you want to include rules to minimize the probability of a statistical run. The handicapping will normalize the odds, you will want to create some favoritism against the leader to minimize the variability.