you've got 3 nodes tightly packed together --- reduce light.
it may take time to recover, and when it does you may need to adjust the light some more... until it matures and can settle in with 'max' dli for your local variables.
In future, take note of light power, distance etc.. map out a safe way to ramp up the light as the seedling asks for it (stretch). you can avoid the excess stretch 'next' time with a good plan. If a plant gets stunted by light, it can take a while to snap out of it and resume growing normally, fyi. Just have to observe and react when it does.
node spacing is a guide to light intensity. Seedlings need less, but will quickly show you they need more if they stretch. if nodes don't space out at all, you know you are giving too much light. It's just something you'll have to learn by doing. As with most things it's not about 'giving more' ... it's about a happy zone in the middle.
No matter the recommendation or the source, always allow the plant in front of you to dictate reality and how to react. Node spacing guides light intensity. LEaf symptoms guide fertilization. etc etc... recommendations are a good starting point but always adjust to the plant in front of you. Great recommendations merely reduce trial and error required. It is always required.
Your VPD (temp and RH need to be considered together, not seperately) is fine. This is not the cause. So, 99.9999999% certain it's the light being too intense.
A wonky VPD can reduce how much light a plant can handle per day (DLI). 70% RH is probably going a bit high, though. You want RH at 65 and below and appropriate temperatures that equate to a proper VPD for stage of life. Over 65% elevates microbial risks. Short-term events of high rh are less concerning but should still be avoided. (rooting clones is a different animal in this regard... high rh is a necessary risk for cuttings)