Chosen Solution

Is it possible to upgrade the motherboard? Maybe replace the internal USB ports with thunderbolt 3? And so on… Is it even possible? I have a lot of soldering equipment.. so that shouldn’t be a problem.

Depending on your exact model you can replace the logic board with one that has a more powerful CPU and RAM. But you are limited to what the series offered MacBookAir6,2 Basically, a 1.7 GHz i7 CPU and 8 GB of RAM being the best you can go with. You can also upgrade your SSD to a larger capacity here’s a good reference The Ultimate Guide to Apple’s Proprietary SSDs with either Generation 3 & 4 SSD’s. Thats all you can do. Consider the costs and keep in mind Apple is about to introduce their own silicon chips replacing the Intel CPU’s. So there maybe more powerful options soon.