Historical house 115 years old and Spray Foam in the attic.

Any advice? Mechanics located up there like our STATE water heater keep failing. Zero to no insulation in a walk up attic currently. Spray Foam?

I have a quote and every trade says yes…my other half says no. Why? This is record breaking heat but it’s a usual occurrence during summer. Attic registers at 135. Upstairs at 88 on the hottest day so far. Why wouldn’t you? Have you? Any issues?