I will be there on first Sunday and admission is free there ,anyway you can prebook an entrance time to skip the long lines?
They're testing a timed-entry voucher system for free Sundays at the Uffizi.
https://www.uffizi.it/en/notices/sunday-how-to-get-into-uffizi
Sorry, can't help you with the Accademia as there's no way to pre-book Free Sundays at that one. If you are staying in Florence the night before, I'd just get in line early before it opens.