This Seeking Tech guide will explain how you can download the free PS5 update for Jak & Daxter from the 2017 PS4 version.
For the first step, go to the PlayStation Store from the home screen menu.
From the shop, you need to search for Jak and Daxter.
You should then select the version with the PS5 and PS4 tags.
Afterwards, you can select the Download option and then Download PS5 Version.