MGS Sons of Liberty still holds up great, and if you can find MGS: Twin Snakes on Gamecube you can play a remaster of MGS 1 with the camera and first person views of MGS2. Recommend.
i try not to talk about video games with someone who can't appreciate anything made before 2008. we didn't always have an entire stick to control the camera with, Jared! submit yourself to the artistic vision!
Oof, I felt this one. I work with a guy who won't play anything older than five years old (I think the oldest game he'll play is like RDR2?), and I've played games all the way back from the DOS era.
I don't know if those games aren't good as recommendations because I personally played the first three (and maybe a few others outside the numbered series?) a while after MGS 5 was already out.
Of course I can't play MGS 5 because I haven't played MGS 4 yet, and I can't play MGS 4 because EVERY other game got rereleased for PC EXCEPT for MGS 4.....
You can definitely play MGS5/V before playing 4, if you've played 3 you'll have 60% of the context needed. Peace Walker and Ground Zeroes make up the last 39%. IIRC the only context you'll get from playing 4 is a few things involving the Les Enfants Terribles project.
EDIT: Thinking on it, if anything playing MGS4 after V might actually enhance your enjoyment of the series as it was fully meant to be a bookend to the series.
For a lot of these jankier old games, I usually recommend watching a long play on YouTube. No commentary and usually done by someone who knows the game well enough to get through efficiently
For the MGS series though there's a lot missed out by not playing yourself, for example if you don't know a thing about psycho mantis, his ability to tell you your save games or to make your controller move across the ground (for those who didn't understand how the vibration in the controller worked) it was pretty awesome. Additionally MGS 3 for example, if you play the entire game without killing anyone (for example using the tranq gun), there's a boss fight where you're supposed to encounter the ghosts of the people you killed but won't if you hadn't killed anyone. The MGS series specifically is just chock full of little things you'd miss out on if you just watch a long play.