When my loans reported, I lost 10-14 points on my FICO 08 scores. I also lost points when the loans were marked as "paid and closed".
Do not rely on what the simulator tells you. I can say that if the school loans are your only installment loan, you will take a hit. The FICO system likes a "credit mix", which includes having an installment loan open.
To your questions on the other threads, the default notation was only noted through the Dept of Education. My credit reports showed the default amounts as collections. The collections were not deleted, they were only marked as "Paid and Closed".