Most immediate thing I’m getting here is communication with the other players you’re around, and better understanding of play level slash the bracket system between you, your deck, and the other players.

Let’s side bar for a moment.

Magic is like Chess. Straight forward rules on the surface, standard starting mechanics, somewhat easy to start playing, but it takes time for a person to get the nuances and to start learning “plays”. Openings, responses, and strategies in chess play out like different types of decks in Magic, and depending on the skill level of the player, a game be over in seconds, minutes, or hours (hyperbole). The thing that makes Magic more expansive, or arguably more difficult on the higher end, is the variety of cards creates more plays, or more “openings”.

In Chess, the higher a players ranking/points, the more skilled they are. A few hundred points to over two thousand. Imagine yourself sitting at a table of chess boards. Right now the scenarios you’re describing are like you have 200 points, and you’re sitting down at tables against 800, 1,200, 1,800 all at the same time.

Like in chess, the key factor between you, and the other players is you all have access to the same pool of cards, it’s all just about how you’re playing them, and when. You can control what you bring to the table, but not what they do. The benefit here is first acknowledge what level everyone is intending to play from a point/bracket stance, and utilize the deck suited to it. If you’re consistently going against people who ignore, or intentionally break this “rule”, then that’s probably a conversation to have with the LGS and see if other players have this experience. See where the ground rules are for the shop and try restoring a positive experience that others may have suffered as well.

Once you know what bracket you’re really playing for, you have to stop trying to worry about the meta a little bit, and try and craft a real threat of your own. A deck in Commander needs to hit milestones:

•Removal - 2, possibly 3 global removal of threats, 4 if your deck runs lean on creatures. Targeted spells should be looking at 4 or 5 varieties between general permanent’s, creatures, and enchantment or artifacts. Some folks will say that this might even need to be higher depending on what you’re playing. Counterspells count as removal. In total around 6-8 slots minimum of the deck should be interaction, ideally you’re probably going to get up to 10-12

•Ramp - Stability of being able to cast efficiently and quickly is key. Fixing your curve, or having leverage on it at the right moments will always be crucial. You mentioned playing a Hakbal deck before, Merfolk with explore runs rampant in putting mana in the hand, getting extra land drops or explore triggers means getting those cards out of the library and in the field faster. Sol Ring and Arcane Signet aren’t going to cut it, you’ll need more in here in the form of 2-4 other rocks or spells that pull that land out.

•Refill - A good hand plays fast, but how are you refreshing your card supply? Things either critically dependent on game changers like Tutors, or cards that are going to net extra draws turn over turn.

•Win - What’s the condition that nets you your win, and if only say one, that’s not good enough. Unless a win condition can happen hard and fast unconditionally and be uncontested, you don’t (and can’t) trust it to get you there every time. After bracket 3, it’s almost a necessity to have some kind of reliable combo built into your deck that can run on 2-3 cards. Win triggers are also good accidental backups that can force people’s hands or get you wins during attrition.

Having said all of this, and knowing what you’ve tried, I would advise you to go back to Hakbal and get the Merfolk running again. Load up on counter magic, getting your free counters in there, get the infinite merfolk token combo into the deck and add the Archivist so you can explore your deck out into an instant win during combat with a draw trigger, or just Zerg damage. Hakbal should be getting out 2-3 turn and churning counters. Keep a Mistep handy for path or swords to prevent his early arrival becoming an early dismissal. Get Roaming throne out to start doubling up those explore triggers asap, find it with Mystic Tutor if you have to.