so you are saying there is a bolt that holds the EGR valve to the tube? how close is the bolt to the EGR valve, right on the EGR Valve? you have to remember the EGR Valve recurulates exhaust gasses which already get super hot, i think you might be ok, my advice to you is to put WET RAGS, soaked and i mean drenched in cold water on all the components around the bolt to keep it from burning, but keep the rags wet when heating try a propane torch first, see if that makes a difference.
when i did break work sometimes some of the bolts holding the caliper on would sieze up on the mounting bracket, the rubber break hose wouldn’t be to far away with some other rubber components, we would put a ton of soaked wet rags all over rubber components, the water in the wet rags would evaporate as we heated up the metal bolt that got hot drawing heat away form the rubber components, but we constantly kept the rags wet, and a fire extinguisher at the ready.
i have no idea how close you are to plastic components, but i would try a propane torch, and keep everything covered in soaking wet rags around it theroughly, and then carefully heat up as you go and see if you can get the bolt to break free, and keep a fire extingusher at the ready, and 911 on speed dile just in case, and keep the vehicle away form any buildings to be safe.
its really hard to tell from the diagram also what components are made of plastic and aluminom too, but like i said, keep the parts you don’t want hot covered in wet rags, and if there is no plastic right on that you might be ok.