Observations re footwear
I have just finished a wet
Camino Frances in walking shoes and took particular notice of what others were wearing.
My impression is that sandals were a rarity, but sometimes worn for a day or so when blisters made boots/shoes unwearable. I did see a pic of pilgrims walking in sandals (no sox) in heavy rain, which seemed intriguing.
Similarly, traditional heavy leather hiking boots were uncommon. I decided not to take mine because of the weight (1.3 kg vs 0.7kg for shoes). In a day's walking you will take over 20,000 steps, so lifting an extra 0.6kg 20,000 times works out to a lot of added stress on the legs! Most caminofoot/ankle problems I saw (other tnan blisters) were due to repetitive over-use of tendons, muscles and joints, rather than acute injuries.
The great majority (90%?) of pilgrims I saw wore either walking shoes or light boots, with maybe a slight preference for shoes.
I found shoes (good ones) perfectly adequate for 800km, even in stony and very wet conditions. Of course, if you have a known ankle problem, boots with ankle support would be a better option. In very wet conditions, both boots and shoes will get wet.
If you go for boots, get modern, light-weight boots with "fabric" uppers.
Also, look for boots that don't irritate the Achilles tendon (joins calf muscles to the heel). Tendinitis is a fairly common problem when starting repetitive, long-distance walking. It can be a show stopper and I saw surprisingly many pilgrims dropping out and also needing treatment for this problem.
Modern boots should have a cutaway in the ankle support at the top rear of the boot so that the support does not rub on or restrict the Achilles tendon. Hard to desrcibe, but obvious when you look at boots.
Also, it can be worthwhile to visit a foot doctor or a good shoe shop that can check out your feet/ankles for potential bio-mechanical problems such as over-pronation requiring arch supports. Over-pronation can aggravate the Achilles tendon and increase the risk of injury.
Hope this helps.
Bob M