I knew nothing about the series and I enjoyed playing Metal Gear Solid (PS1) this year.
At times it was also really annoying and I needed my partner to motivate me to keep playing it. Usually I was approaching something wrong or I just needed to take a break. I think I restarted on easy difficulty.
Note that it's prominently about the story and has long cutscenes.
A certain part of the game is experienced much better on original hardware than emulator, so if you do have a PS1 laying around, plug it in. If you don't, emulator is fine.
Apparently the sequel is better but I got demotivated too early on.