So, the spamming cuckchanner who communicates almost entirely in reddit "jokes" and 4chan insults hates Metal Gear Survive and Metal Gear Solid 2, but loves Metal Gear Solid 5 and Metal Gear Solid 4? Well I, for one, am utterly shocked!
At least 4 had a reason to exist, it gave the series an ending and wrapped up the main storyline, whatever it was. 5 was almost entirely pointless in terms of the overall series. Also the gameplay in 5 was terrible.
I think we all know the best Metal Gear game is the one Kojima had little to do with: Metal Gear Rising.
MGS4 had absolutely no reason to exist and even Kojima had to be forced to work on it. Hell, he wanted to give his director role to someone else to "pass the torch" but he got literal deaththreats from his deluded cult of a fanbase so he begrudgingly directed once again.
MGS4 has little to do with MGS2, aside from the fact you are taking on Patriots, it was just a nostalgia wank all the way thru. MGS5, on the other hand, expands on Big Boss saga(more interesting than Solid Snake saga in my opinion) and brings the franchise that much closer original Metal Gear and the Outer Heaven. People always wanted, and still do, a Peace Walker like simulator on proper consoles(remember, PW originally came out on PSP and was ported over to 360 and PS3 unchanged) where you actually get to build up Outer Heaven, this was even teased at the end of PW. MGS5 was an inevitability(Peace Walker was originally called MGS5 btw), where as nobody wanted a sequel to MGS2, the franchise wrapped itself nicely at that point in time and the future of the franchise was clearly going back to the past, with MGS3 released afterwards. Everything about the ending of MGS2 tells you to move on and make your own future: Snake doesn't have to be a soldier for the rest of his life, and Raiden doesn't have to try and appeal to anyone and can be his own man instead.
Then we finally get MGS4 and Snake is literally an old man still fighting in wars(right down to having a stress meter lmao), and Raiden becomes a cyborg ninja in an attempt to get the fanbase to finally like him. MGS4 is almost a parody of what a Kojima game would eventually look like if it was a perpetual sequel hell like COD, except it actually happened and released as full priced product. The ending of MGS2 is thrown right out of the window right from the start.
I will give you that, the fans wanted a PROPER sequel to MGS2, where the Patriots are taken down, and maybe it would have been good if it was handled properly. However, MGS4 wasn't that, in fact MGR does a much better job of being a futuristic Metal Gear, as well as actually starring Raiden to highlight that he is the protagonist now instead of bringing out grandpa Snake in his wheelchair. Even MGR was unnecessary however, as the ending of MGS2 clearly states to LET IT GO AND MOVE ON WITH YOUR LIFE. Patriots are seen as bigger than life foes that would never be taken down even by someone like Snake, you're not supposed to fight them. Thankfully, MGR realized this(that and the problem kind of solved itself in MGS4) so you get a fun new villain that betrays all expectations, instead of skinwalking some other villain from the franchise's past. Funnily enough, MGR also gets the point that MGS4 was trying to get across much better too, despite the writing now almost being on a level of a shonen anime more than anything.