A:AnswerRAM is two standard SODIMM sticks. Easy to replace, just be careful getting the case off!
To my knowledge, you can get up to 64 gb of DDR5 shared between the two ports.
A:AnswerYou can play your Xbox titles on game pass on this machine and most likely you can hook your Xbox up to some sort of capture software if you also purchase the correct hardware but generally no this isn’t usable as just a portable monitor.