To get user/teams details of who made the changes you can try below formula. It is a polymorphic lookup you have to write formulas in such a way to get the data. Below snippet is an example of getting user or teams name for label inside gallery.
We can't get granular details like we get it inside powerapps audit summary view. To summarize, it will be very hard to get record information, because you might have enabled audit for entire organization or for few entities. In such case, you need to write formula like above for all the entities where audit has been enabled.
Since "changed by" involves only two entities user/team so it is easy to write formula and also no changes required. If it is for multiple entities your formula will get complex and in future if you create any new entity with auditing enabled, then changes required everytime in the formula. I would not recommend that way.
I hope I have provided necessary information.
If it answers your question. Kindly give kudo and accept it as solution.