Prop them up on something like bamboo or sticks. then move the light a big closer as they are stretching to much,
I use the sf1000 and I used it as 100% from seedlings but I had it hanging quite high. it is only 100W so its hard to burn your plants with it but not impossible.
They will take some time to establish themselves and even then your main stem will most likely always need some form of support till its much bigger.
Good Luck!
***disclaimer, multiple people are answering all questions as there is a contest called GOTM, when a user is selected as the answer they get a point. Please see the contest page for information regarding the details:
growdiaries.com/giveaways/GotM-August-2022
Please note, when you reply to anything on the questions part of Growdiaries website, no one will be notified of this. Not even if you use a "@" tag in their name. Best to reach out to them in DM using your inbox, it can be found in the bottom right hand corner of the site. It's the small paper airplane button, it will be highlighted green if you have new messages***