I’m an orthotist.
The recognized approach with plantar fasciitis is to treat the underlying cause rather than plantar fasciitis itself. I’d suggest you get feet checked out by someone who has a specialism with feet. That might be a orthotist, podiatrist or possibly a physio. Where are you based?
Insoles are popular but personally I think they are over-prescribed. The evidence that custom made insoles offer better outcomes than off the shelf is quite weak. The general principle with insoles is to apply an opposing force to the relevant structures of the foot in order to give relief. The old school theory from about 25 years ago was that insoles principally provided ‘correction’ to a neutral foot position. Despite the advancement of understanding, insoles are still regularly marketed as doing this. Off the shelf insoles are often perfectly fine for plantar fasciitis. Worth getting your feet checked out though so that there’s a clear treatment strategy. You might just need a few stretches.