Heel spurs are tough. I had them and they were very painful first thing in the morning.

A good way to stretch the plantar fasciitis on the bottom of the foot is by massaging the arch. This loosens the plantar fasciitis and eventually should give some relief from heel spurs. I have found the best way is to use a golf ball and roll it under my foot everyday. You can also stretch the plantar fasciitis. Here are some ideas:
https://samuraiinsoles.com/blogs/bing/plantar-fasciitis-stretches-bing?msclkid=7d56fc44318f1b09e7119b086ec5bbdd
But it sounds like Voltaren Gel could help. All the best to you! Joe