Chosen Solution

I have an iPhone 6s that is very much broken. The screen is blank and it won’t turn on. Its not being detected by the computer nor does it switch on. The service center said the problem is at the board level, is there any way the pictures and other data can be recovered that haven’t been backed-up to iCloud?

The only way to recover data from an iPhone 6S is to repair it enough that it boots and is recognized by iTunes. As you say, this will require micro-soldering expertise and is not a DIY repair. Look locally for a reputable shop that does micro-soldering repairs and data recovery. Ideally, you want to find someone local but good workmanship trumps locality. There are many shops worldwide that do this so you shouldn’t have any problems finding them..Talk to them and ask how they do their work. Focus on troubleshooting, as opposed to shotgun replacement. If you can’t find one locally, then consider mail-in repair. There are several reputable micro-solderers patrolling this forum.