Missed OTR – Can I Still Fill the Form without OTR?

Hey everyone,
I have a doubt and would really appreciate some clarity. I didn’t complete the One-Time Registration (OTR) process before, and I also haven’t done it at any time earlier.

Now that the SSC notification is out and the application window is open, I’m wondering:
Is it still possible to do the OTR now and fill out the form, or have I missed my chance this year?

If anyone has gone through a similar situation or knows the official process, please help out. Thanks in advance!