There is always lots of discussion about whether the feet should be flared, square, turned in, etc.
Just like most things in the golf swing, it is very individual and dictated by how you swing the club and what mistakes you make or physical limitations you have.
To me, the right foot (back foot for righty) should never be flared intentionally. It can cause over rotation and getting the club behind you and it can also make it difficult for your lower body to clear in sync with the shoulder turn.
If the right foot is flared, it is a long time thing that came naturally and it causes none of these problems, then there is no need to change it.
I like the right foot to be square/perpendicular to the foot line. Turning the right foot in is not always a good thing, because if you are inflexible it can restrict your movements.
Turning the right foot in as a drill on the driving range is sometimes helpful, but a square right foot is going to be most effective for the vast majority of golfers.
The left foot (front foot for righty) has a more flexible range of how to place it. Many people get a great benefit from flaring the left foot to give the lower body more room to clear. Those with over active lower bodies that get out in front and get the swing out of sync, may benefit from a square or turned in left foot.
I can’t tell you individually what to do, but you can use this info as a guide to tinker yourself.
I will leave you with one last one. When chipping and pitching, you may find it very helpful to flare the left foot and turn the right foot in. That will put them parallel with each other. There is a double benefit for this.
One, the turned in right foot will help you keep the swing shorter for better acceleration on a short shot. The flared left foot combined with the turned in right foot kind of sets the hips in a “pre-cleared” position and allows you to have the lower body out of the way while allowing it to be very quiet.