Buck is nowhere near the most problematic class in the game, imo. It's certainly the easiest to pilot, largely in part because of how easy it is to slap on some shields and strength buffs then go to town. This playstyle is fairly successful and dominant against inexperienced players, but that doesn't mean buck is "busted." Some tips on how to deal with them (I don't know your class, so I can't give you anything ultra specific):

• Reduces are your friend. A well-timed reduce (from a pet or from bazaar gear) makes a buck all but helpless during its duration. Their only real way to chain is off super lucky lands and the strength-based bladestorm 3. You can follow up these reduces by having any swashbuckler units you have attack the now-reduced buck. First Strike and Riposte chains will shred any buck outside of elusive.
• Use Ratbeard. Ratbeard is the single best unit against a buccaneer. He can get first strike 3 and repel 3, making it hard to rapidly kill him and greatly punishing any buck that approaches and triggers his repel. Ratbeard also has a reduce of his own, a super strike (this is probably Rat's worst attack against the buck pirate, since it will almost always be well-shielded), and a knockback. This knockback is particularly potent as it ignores any trained buccaneer shields, allows you to set up combos with traps/bombs (musket only), and forces the to walk into his repel again.
• As a swashbuckler, I've found that many buccaneers are unwilling to use their forts early (or only run a total of one), instead opting to use Leviathan's Calls stacked with the occasional Valor's Shield. I've been able to take great advantage of this playstyle decision. I often use companions that have attacks that ignore levy (Ratbeard, Baar, and the Armada Dragoon all have 1+ of these attacks, as well as relevant counterepics and other powerful attacks). This allows me to rapidly pressure their life total early, forcing them on the back foot and giving me control of the match. If you notice that your buccaneer opponents aren't using Forts, you can use attacks that get through levy early in the match to gain a massive advantage.
• NEVER WALK INTO HTL UNLESS YOU HAVE A CLEAR PLAN TO KILL THEM IMMEDIATELY (or are reducing them on the last round of one of their 50% shields). As you get more experience, you'll find a few exceptions to this rule, but for now, it should be taken as a hard and fast rule. You will die to Frenzy or some other attack + ensuing chains, particularly if they're not reduced. Thus, opposing melee players have to use their hides and reduces intelligently, as they are your only way to initiate an attack after your units die.

Matthew525011 on Aug 2, 2019 wrote:

Buck is nowhere near the most problematic class in the game, imo. It's certainly the easiest to pilot, largely in part because of how easy it is to slap on some shields and strength buffs then go to town. This playstyle is fairly successful and dominant against inexperienced players, but that doesn't mean buck is "busted." Some tips on how to deal with them (I don't know your class, so I can't give you anything ultra specific):

• Reduces are your friend. A well-timed reduce (from a pet or from bazaar gear) makes a buck all but helpless during its duration. Their only real way to chain is off super lucky lands and the strength-based bladestorm 3. You can follow up these reduces by having any swashbuckler units you have attack the now-reduced buck. First Strike and Riposte chains will shred any buck outside of elusive.
• Use Ratbeard. Ratbeard is the single best unit against a buccaneer. He can get first strike 3 and repel 3, making it hard to rapidly kill him and greatly punishing any buck that approaches and triggers his repel. Ratbeard also has a reduce of his own, a super strike (this is probably Rat's worst attack against the buck pirate, since it will almost always be well-shielded), and a knockback. This knockback is particularly potent as it ignores any trained buccaneer shields, allows you to set up combos with traps/bombs (musket only), and forces the to walk into his repel again.
• As a swashbuckler, I've found that many buccaneers are unwilling to use their forts early (or only run a total of one), instead opting to use Leviathan's Calls stacked with the occasional Valor's Shield. I've been able to take great advantage of this playstyle decision. I often use companions that have attacks that ignore levy (Ratbeard, Baar, and the Armada Dragoon all have 1+ of these attacks, as well as relevant counterepics and other powerful attacks). This allows me to rapidly pressure their life total early, forcing them on the back foot and giving me control of the match. If you notice that your buccaneer opponents aren't using Forts, you can use attacks that get through levy early in the match to gain a massive advantage.
• NEVER WALK INTO HTL UNLESS YOU HAVE A CLEAR PLAN TO KILL THEM IMMEDIATELY (or are reducing them on the last round of one of their 50% shields). As you get more experience, you'll find a few exceptions to this rule, but for now, it should be taken as a hard and fast rule. You will die to Frenzy or some other attack + ensuing chains, particularly if they're not reduced. Thus, opposing melee players have to use their hides and reduces intelligently, as they are your only way to initiate an attack after your units die.

An example of reduces that Matthew is talking about ( if you're new and don't know ) is Bonnie Anne's scattershot and if you trained her to overwatch 3 the is an accuracy reduction if she hits. You can get gear that grants Cruel or Brutal Charge ( Buck's major debuff ) from the bazaar or drops/pet grant.
Maybe get a few shields for yourself as well.