Depends on your strategy.
You can definitely give a hard paywall a try. Just test it out and see if it makes you money. Many people saw success with it. For many of my apps I have a soft-hard paywall. I give limited free access, and even the free access the users need to watch rewarded ads, so it makes me money if they use it for free.
If you use RevenueCat I recommend using experiments to make A/B tests with different paywall copies.
One thing I do for feedback rating is: I place a thumbs up and thumbs down button on the screen I show results (for example). If user presses thumbs up, it triggers the rating dialogue. Since they pressed thumbs up its more likely the give a positive feedback. If they press thumbs down I open a report dialogue and ask for the improvement. So even then they feel like they have been heard (I am not reading this shit tho, most of their reports are because of dumb shit literally wasting my mailbox storage space)
So basically showing the rating dialogue whenever they had a positive experience.
I wouldnt recommend randomly showing the rating screen, especially when they use it first. Most will dismiss it or even give a bad review.