

2012 and earlier or the newer 2018 model all have socketed memory and can be upgraded it is only the 2014 model that does not. Any DIY attempt would merely destroy either the logic board or chips or both. However newer logic boards, chips and manufacturing techniques mean that these days an ordinary soldering iron is totally useless for this purpose and you need tools equivalent to those used originally to build the logic boards, as such it is not possible unless you are a major manufacturer and they have no interest in doing this. ) I remember some enterprising people doing this to upgrade the original Macintosh 128KB to a 'Fat Mac' with 512KB, I even had this done to my own one back in 1985. Holy moley The Apple Mac mini with M1 processor is cheaper, faster, and keeps everything we loved about the Mac mini while changing up both the internals and where Apple sits in the larger industry. In theory one could unsolder the existing chips and solder new bigger capacity ones, this indeed did use to be commonly done in the olden days.

This leaves the only option as being to sell it and buy a better model. The 2020 Intel mini is still available and that’s what crucial and others are selling memory.For the Mac mini 2014 the memory is as you state soldered to the logic board, as such it is generally regarded as impossible to upgrade the memory. Pick any ten apps you want to start and race the entry level Air with any Mac of your choosing - iMac Pro, Mac Pro, or an 8 core MacBook Pro - there are only few specialized tasks where the Air is slower. Real world benchmarks are showing them completing work dramatically faster than 12 core Mac Pro with 32 GB of RAM. I would not mistake an 8 GB RAM Air, Pro or Mini for anything but a beast of a workstation for most tasks.

Everything is soldered to the logic board for Apple Silicon Minis. The SSD chips have separate placement on the logic board from the Processor board. Many Apple users will be happy getting an upgrade at an Apple store or doing so via a tech professional. Apple advises allowing an Apple Store or Apple Authorized Service Provider to do the upgrade. There is no slot or place to add memory on the M1 based Air, Pro or Mini. The 2018 Mini’s RAM is upgradeable, but its a much more complex process than that of the 2010-2012 Minis. RAM Memory on the Apple Silicon M1 Processor is integral to system package “chip” that’s mounted as one unit to the logic board.

No RAM upgrade - you would need to reflow new processor board or be skilled enough to rework the one you have.
