You can repot them in a bigger pot and bury the stem as much as you want and either yes get a stronger light or move them closer to the light you have now.
You also don’t want clear cups. You don’t want light getting to the roots.
You better fill out a grow form, if those plants are a month old you have multiple issues. A month old plant should be over a foot tall with multiple branchings and lots of healthy growth.
That was a month ago the seeds went into the dirt, not sure if I was clear about that. Also the light I was using was only like 45 watts. I just installed a 1000 watt grow light