Plantar fasciitis won't freaking heal

It's been probably more than a year now and my dang foot won't heal. It's only in one of them. I've tried every single sole there is, every brand of workout shoe, inserts etc.

Resting is not an option. I won't stop working out and I walk about 10k steps a day minimum. I have 3 dogs so I can't stop doing that. I lift heavy and don't want to stop. I have a Spartan race in a month and was going to start running again to set myself up better. But I'm scared to. Right now it feels worse than in a long time, it normally goes away with activity, now I can feel it when walking.

I've lost 50 pounds and still need to lose 40, I know that it plays a part , but it takes time and I can't rush it.

Any ideas for this? I'm stubborn as hell, but it's been over a year. It has to heal at some point?