Chosen Solution

I have a late 2014 mac mini with 4GB RAM. I already replaced HDD with SSD but some apps, even World of Warcraft can cause the system to hit swap. I use it as a secondary device for macOS experiments and alike from time to time… so I’m thinking about doing a bit risky mod - replacing existing Samsung K4E8E304EE-EGCE 8 Gb x 4 with chips of higher capacity and 178FBGA package - like K4E6E304EE-EGCE which are 16Gb. Is it technically possible or is there something that would prevent such swap from working?

I would just get a replacement logic board which has the max memory this system can support Mac mini A1347 (Late 2014) Core i5 1.4 GHz Logic Board Replacing the the chips is very risky! You need the proper tools and skills, you also need the schematics and board views so you can adjust the resistors so the chips are recognized. Without the documentation you’ll have a hard time figuring it out. If you don’t have the tools and have never worked with BGA chips this would be a foolhardy endeavor.