Ours doesn’t actually go into studs, but through the drywall and using metal drywall anchors I believe they are called. He used large metal toggle ones.
One’s like this
It’s ridiculously sturdy, I have no concerns or worries about it, even with the arm extended.
Edit I should note that the reason ours doesn’t go into any studs is because that wall doesn’t seem to actually have any. The house we’re in is old construction and built a bit weird in places. The wall with the tv is kind of like a mini wall separating the kitchen and living room that seems to have been added at some point, with door ways on both sides. Our handy man said its basically a wall made from wood slats going horizontally with drywall nailed into that. So when he drilled through he had to go through wood slats as well. Part of the reason we got our landlord’s handy man to do it was because we were having a hard time getting through the drywall to make the holes for the bolts and couldn’t figure out why. Plus we started to figure, expensive tv, wall mount, lets let some one who knows what they’re doing mount it all.