I'm extremely near sighted. Anything more than 2' away is a complete blur if I don't have my glasses on.
One of the major problems in RDR2 first person, is the movement. Making Arthur turn, can be a challenge because he wants to walk sideways a lot instead. Think original Doom movement. Yes, you can get a front row view of something so close you're scraping your nose, but at the same time, you're not seeing the area around you. Riding is extremely difficult in first person. Forget hunting and fighting.
Another thing that makes third person a preferable choice is the rate at which it switches automatically in cut scenes. It leaves first person to show everyone involved. Most of the time it will return you to your chosen view afterwards, but on a rare occasion it will put in the other. I've come out of a cut scene confused because I couldn't see anything, only to realize the game put me in first person mode. Your view of the surrounding area is wider in third person, at least with this game, whereas in first person, all you can see is what's directly in front of you.
I won't lie, there have been a couple rare instances where I have switched to first person intentionally. That was so I could get a closer look into a tent in a camp I was looting. After I was satisfied with that, I instantly switched back to third person.
First person also defeats some of the features of the game, such as outfits. You can buy different outfits for Arthur, and groom his hair and beard to your liking, but if you play in first person you'll never see it, so there's no point in that. And if you lose your hat, how are you going to know it? You have no real way to know except to open third person. You can get on your horse and check to see if it has a check mark by it in your item wheel. If it doesn't you can select to put it back on, but in reality, how often are you actually going to be checking that? The same goes for your horse. You can customize his/her mane and tail, but you'll never see them in first person. And you have to keep your horse clean to keep it healthy. You don't really have time to constantly look down while you're riding to make sure it's not completely filthy.
Dutch rides a solid white horse, the same as me. So I colored my horses tail black as an means of telling them apart.
There is other customization you can do, but that's just guns. The only ones I carry in the beginning are the Springfield rifle and varmint rifle. That's just to get the hides needed to get the Legend Of The East satchel. After I get it, the varmint rifle is stowed away in my weapon locker. You can choose the metals, the wood of the stocks, carvings and engravings, and it goes over every last part of the gun. You can have a solid gold gun if you want. If I remember correctly there are around 16 or so woods and 8 metals. And you can mix and match all you want. I have a pearl gripped pistol.
And if, like me, you have a hard time playing a game the employs a dual joystick, the third person can help you learn. I was never able to do it prior to RDR2. It was one of the reasons I didn't like Skyrim initially. But I've learned pretty well to utilize them both, and I have no severe issues left, only minor ones.
Basically what I'm saying is that for this game specifically, third person is the best choice. It's nothing like the first and third choices in Skyrim. It's a hell of a lot different. In Skyrim, you can always see your hands in front of you. That's not here in RDR2. Not any time I have played it anyway.
In the video below, he was in Bloger Blade when he made camp and looked at his legendary animal map.
At the 15:00 mark, you're able to see one of the bigger issues when riding in first person. That was in St. Denis.
It was difficult to find a video that gave no spoilers, and all of the ones I found, that featured third person views included spoilers.