All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.
We restricted the answer in the fatwa (320119) that you read to the case when part of the prayer is performed after the end of its prescribed time. So if the worshiper knows that the congregation performs the whole prayer within its prescribed time, then he should pray with them and not pray individually.
However, if he knows that part of the prayer is performed outside its prescribed time, then he should pray alone. Afterwards, if he wishes, he may pray with them, and it will be considered a supererogatory prayer (naafilah) for him, as was clarified in the fatwa that you read.
We think that starting the prayer 25 minutes before sunrise is enough to perform the whole prayer on time; in which case you should pray with the congregation.
Allaah knows best.