It’s your decision whether to play to the character (roleplay) or play to the mechanics (meta-game). There are good and bad points of each, depending on your perspective.
Perhaps your character really is an all-knowing, megalomaniac, murder hobo, but more likely they’re someone with their own desires and flaws, just like everyone else. The meta-game is about using out-of-game knowledge to influence the game and can sneak in through a warren of shady alleyways. It can make the difference between a character-focused roleplay game (Dungeons and Dragons is a storytelling medium at its heart, after all) or a mechanics-driven hack fest.
A few ways to avoid the meta-game are through thinking about group dynamics, character build and character knowledge. A little tweaking of any of these can give you a more functional group and enrich the experience for everyone.
Every table is different, so you need to consider how your play style fits in with the rest of your group. Critical Role, for example, is very heavy on the roleplay and that’s the accepted approach of the group. Other groups might be all about squeezing out every point of damage possible with little interest in what or why they’re fighting. Everything can be solved with a fireball, right? A hardcore roleplayer may feel out of place in a meta-group, while a meta-gamer might become frustrated with a bunch of roleplayers.
Players, particularly in newly formed groups, can be anxious about how much roleplay to do. Nobody wants to get shot down when they’re enjoying their game. It’s worth testing the water with some light roleplay first, gauging the response of the group, then keeping it to a level that everyone is comfortable with. Some might follow your example and get more involved. If everyone else looks at you like you’ve just burned their character sheets, you might want to tone it down a bit.
Not every adventure has to be a hack fest, just as not every encounter is a fight. You may be forced to deal with puzzles, traps or creatures where combat prowess doesn’t help.
Combat is a major part of a D&D game so you probably don’t want to be sat there twiddling your thumbs while the rest of your party deals with the threats. Granted, it could make for interesting roleplay opportunities if you’re playing a coward or someone unskilled at fighting, but you have to decide whether you’re happy with not being involved in combat. Appreciate that your group may become frustrated with you for this!
Putting all your eggs in one basket can be disastrous. When a draconic bloodline sorcerer puts everything into fire spells then meets something with fire immunity, they’re in big trouble. I fell into this trap when using a storm sorcerer and going heavily into thunder and lightning. As a player, you can feel lacklustre when there’s nothing you can do to hurt the creature you’re fighting. With a little thought, it’s possible to have some combat utility while keeping true to your character. Your character may desire nothing more than to run a tavern in the country, but necessity has them learn the skills to defend themselves. Having a range of abilities opens options for dealing with encounters in creative and interesting ways and can enrich the whole experience.
Sure, you might know how to deal with a vampire, but has your character even heard of them? Oddly, character knowledge can be much easier for new players to get to grips with since their knowledge is limited. Experienced players who know the Monster Manual back to front and inside out, however, may have trouble switching off this knowledge.
When it comes to your turn, the question isn’t so much ‘What would I do?’ as ‘What would my character do?’ True, you may not be dispatching enemies in the most efficient manner, but you won’t be breaking that connection with your character.
Hopefully that gives some ideas on keeping the R in RPG. I’m interested in how other players avoid getting too sucked into the meta-game. Leave a comment if you have any words of wisdom.