curly leaves burnt tips

Definitely heat. as far as lux, it won't travel well from one light to another. it can give you a good idea of intensity for your light, but if the spectrum is not the same the lux measurement will be drastically different and not neccessarily correlate to PAR/ppf/ppfd etc.. a lower lux could have a higher number of photons/s that matter. since it's damaged, go to 30" until it heals and starts to grow. Avoid it stretching if it does. i'd bet ~24" is a good ballpark to start from once it is growing vigorously again. Try moving up from there and see how it reacts at 22, 20 etc.. then dial back at first hint of a negative reaction.

High there! Seedling need around 5000-7000 lux of light. Vegetative = 15000 - 50000 lux Flowering 45000-70000 Lux. Full direct sun = 120000 lux. You can found some luxmetre on any smartphone apps store. This is not the perfect solution but it can help you to find starting point. There no need to run 600watts lamp for the first 2-3 week. Low heat light like neon or small led will do a perfect job making this much easier to deal with. You can also add some dome(toped plastic bottle) to keep the HR% stable. Good luck with this :)

You did good by moving the light up when there a seedling they don’t need much light at all. What is your humidity at? Also I don’t recommend getting your tent that hot I say usually run temps 75-85 at max unless your running co2. But when in the next few days with the light up you will see her bounce back.🙏🙏👍👍👍