There are optimized builds for every set of roles and responsibilities in a group. Some may need more weapon damage, some more spell damage, some larger resource pools, some more resource regeneration, and some more defensive stats. The gear, enchants, and skills that you use / equip / put on your bar are what determine if you have the potential to be great. Good gear does not make a good player, but it does give the player a higher likelihood of success.
Every individual has a role and responsibilities. Some examples are: Stamina DPS, Magicka DPS, Disruptor (disrupts the opponents with cc), Protector (ensures that certain key members of your group don’t get targeted) and Healer. Note that there is no such thing as a tank in PvP, or rather a PvP tank doesn’t serve much purpose other than to be an ultimate generator for opponents.
If you come into PvP thinking you’ll be “the tank”, very few good leaders will want you in their groups. There is a requirement for “tanky” players to assume other roles (such as applying defile or other healing debuffs to opponents), but there is no dedicated Tank role as there is in PvE since you have no control over who your opponents attack. If they think even a little bit about what they’re doing, they will target the high priority players first (such as known group leaders, healers, or high damage doers) – not the person who will last to the end of the fight who doesn’t do anything useful. It can be fun to be “the tank” and last a long time before dying, though you should also consider that you’re not going to make very many points by just standing there holding block.
Be very wary of taking advice from people. People build biases based on what they like to do, not necessarily what is best for them or their group.
Be even more wary of copying the builds you see popular streamers use. Many of them have a very niche play style, and tend to play for their audience rather than to be good at the game. I often call many of these players “1 v Potato” players rather than their self-titled “1 v X’ers”. If you see one person kill five others, then it’s a near certainty that those five others were not very skilled. In most situations, one player vs two other players of the same skill level will result in the one player dying / losing. In some cases the two may be outplayed, or one may make a mistake, though when considering equal skill it’s very unlikely for an outnumbered player to win. This is of course what many of the “1 v X’ers” count on, as it promotes their stream and brings in more fans who will help them make more money. The exception to this is usually an Emperor (the the Emperor section for more info) who, as a good player with an appropriate Emperor build should easily be able to take on five other players if using the right strategy.