@InvaderXan you can do a lot with a good microscope, tweezers, a heat gun, and flux, but good tools are expensive and tool libraries are rare. I recently replaced a nexus 6P phone battery with a partner using an iron, some eyelash tweezers, and a patience, but modern devices really aren't designed to be repaired or upgraded :/
It's true, good tools are hard to come by and replacing parts requires skill. But then, in some countries, there are independent high street phone shops which will replace your old battery or swap out parts for little more than the cost of labour. I got an extra couple of years of life out of an old phone by getting a new battery at one of these places. Much cheaper than manufacturer prices too!
"I appreciate SDF but it's a general-purpose server and the name doesn't make it obvious that it's about art." - Eugen Rochko