ugh shoot, you are right I was thinking about my old MacBook and the iMac.
but, I know 3 beep happens because of bad memory module. :(
soldered memory modules definitely limits your options there. maybe you can cry to do a cleaning with some pressured air to make sure there isn't some shorts etc.
(unless you are good at soldering bga chips).
you might want to check this link I hope this helps
https://www.macworld.com/article/2362040/do-you-have-bad-ram-how-to-find-it-and-how-to-fix-it.html
I believe there was a way to disable a memory module from terminal. I will reply again if I can remember it.
(it would cut the amount of your memory in half but should at least make the laptop stable).