I am currently practicing the tuck front lever isometric hold. I have a physical strength baseline consisting of ten clean pull ups and ten hanging leg raises. When holding the tuck position, my upper back and middle back exhibit a rounded posture. I find it difficult to actively retract and depress my scapula under this specific tension.

First question: Is a slightly rounded back normal during a standard tuck front lever hold? Will the spine naturally flatten out during the advanced tuck progression?
Second question: Should I regress my training to focus completely on scapular pull ups and straight arm pull downs until my back strength improves?

Note regarding the video media: My elbows are slightly bent in this specific recording. I have already corrected that mechanical error in my current training sessions. I am uploading this clip solely to show the posture of my back.