But in the Bible, Jubilee is every 50 years.
That is 100% true, the OT jubilee’s were indeed every 50 years. In Leviticus 25:8-13 says to make every 50th year a Holy Year for the people to reflect and remember what the Lord has done for them and to give thanks to Him.
Deuteronomy 15:1-2 a more ordinary form of the jubilee was established every 7 years, but the 50 year one per Leviticus which was much more in depth is still to be celebrated in the Jewish Liturgical worship calendar as one of their religious feasts.
So around the 1300’s or so the Popes began to put a 25 year jubilee on the Catholic Church’s Liturgical calendar. Pope Boniface VII seems to have been first and it was varied from 25 to 50 years, you might have one then next time 30 or 35 years or 50 years, etc.. By the time of Pope Paul II in 1470, the Jubilee years were fixed to be celebrated every 25 years so the Church already has set in its Liturgical calendar when the next Jubilee year will be celebrated, which of course will be 2050