You might be confusing EEA FP and EUSS FP.
June 30th 2021 is the deadline for applying to the Scheme as a EU national, and also the deadline for applying to the EEA FP, and use it to come to the UK, as a non-EU national.
June 30th 2021 has not been communicated as the deadline for applying to EUSS FP, nor as the deadline to arrive in the UK on a EUSS FP. As far as some of us have been able to interpret from the information available, there does not seem to be a deadline for EUSS FP applications or arrival in the UK, and the only clear restriction is that the application to the EU Settlement Scheme needs to be done within 3 months of arrival in the UK (see
this post).
My posts express what I believe are the facts, based on the best of my knowledge, about the topics discussed in this forum. They do not constitute immigration advice.