I'm actually kinda shocked that so many people are saying bloodborne is the better entry point for the 'series'.
That's really all I need to say He is such a potent road block so early on (Could end up being your first boss if you someone don't meet the Cleric Beast), and he remains one of the hardest in the entire game. Nay, franchise. Bloodborne is far less forgiving than Dark Souls III, and that's a perfect way to show that.
I still think Bloodborne is the best overall, as it demands the most out of me and is the only one I feel I haven't mastered even after a dozen full playthroughs, but that's exactly why I don't think it's the better entry point over Dark Souls III, which I found to be far more forgiving.
I played them in this order:
1 - Demon's Souls (Got about 1/3 through it then had to move on, I hadn't yet got gud)
2 - Bloodborne (Beat it multiple times, got the platinum trophy)
3 - Dark Souls II: Scholar of the first Sin (Hated it, made it about an hour in and gave up)
4 - Dark Souls III (loved it, beat it multiple times, got Platinum on it)
5 - Dark Souls (Beat it, but didn't care for it much; hated half, loved the other half)
So I had a peculiar journey with the souls series. I didn't have any of that nostalgia tainting my opinion of II by comparing it to I or III so my distaste for it was pure. Dark Souls II was my first entry into the series and it almost made me say no to Dark Souls entirely, but then I played 3 and loved it, and I played I and thought it was okay. Then, after Dark souls Remastered came out I played THAT and fell in love with it. Went so far as to get the Platinum trophy on it, which felt great. I put it just one point below Dark Souls III (which is still my favorite, barring Bloodborne.)
So yeah, even without bias, and after trying to play Dark Souls II multiple times (after I beat bloodborne but before I got the Bloodborne platinum, again after I got the platinum and before I played III, after I beat III but before I got the platinum, and again after getting the platinum on III and beating I for the first time), which tells me it's just not good enough. Dark Souls is iconic, memorable, and well designed for the most part but it shows its age by being clunky and possessing some terrible bosses (Bed of Chaos, Capra Demon), while III is basically I but with polish and nary a bad boss in the entire game.
But I'm rambling.
Bloodborne is my favorite getting a 9.7/10, but I wouldn't say it was the best for a beginner.
Dark Souls III is my second favourite, getting a 9.5/10, and I'd say that it's the most approachable of the whole franchise
Dark Souls I is my third favorite, getting a 9.4/10 and I'd say it's wonderful but not the most newbie/user friendly
Demon's Souls is nice but it shows its age
Dark Souls II misses the mark and feels bad to play and lacks so much of the iconic stuff from I or the refinement from III.
My vote still goes to III for your first game, then go back to I and then Bloodborne. Those three are all masterpieces. Avoid II at all costs, and I can't really recommend Demon's Souls, even though it's a good game.