It is a small project, I would recommend to start with Joomla 4.
Joomla 4 is really good, it is a next generation CMS, and at the same time the workflow and the interface are quite similar to what we are all used to in Joomla 3.
So, do not worry, you will get used for an hour
I also do not think that the different jQuery version will be an issue.
In short, give Joomla 4 a try, everything should be fine and you will get familiar with it.