I'm the same, feet, ankles and legs, go crazy in the heat!
I have special shoes which have a netting bit round most of the side and top of my feet but are meant to help keep your feet cool, got them from TJ Hughes and they are great! I can get them on without bending and they are quite roomy for when they swell and very comfortable with insoles in. They have a Velcro bar over them but I can get them on my feet with it over and it keeps them on your feet so you're not overworking the muscles and such (tip from podiatry) trying to keep slip on ones on.
They don't get rid of it all but do help. I got some cooling insoles from Aldi too, a while ago though so not sure if they still have them.
I have a special footstool at work which has a rocking action so I can move my feet to help the circulation and do similar at home, getting them up to drain the fluid on cushions (I have a boat cushion to keep them up), as high as comfortable. Generally keeping them cool too.
When I get home I run them under cold water or use a cold spray and get them up. I use cold/pain gel to help if they are causing problems at night and keep a fan on them as has caused issues getting comfortable enough to sleep in this warmer weather. Don't like keeping the fan on all night if I don't have to, but better than not sleeping.
I've been checked out for kidney and heart causes but nothing so probably my RA. Have had a couple of short courses of diuretics, but not much help overall and told not good longer term due to side effects.