Help me understand the release schedule and meta cycle length

Hi! Getting back into Yugioh and started with BEWD and the legendary modern decks 2026.

Those are cool, but to be honest the two decks I REALLY like in dueling nexus simulator are a Darklords/Solfachord deck and a K9/Vanquish Soul deck.

Both those decks cost a bit of money IRL. I’d like to buy the singles off TCGplayer or whatever, but before I pull the trigger, I’m trying to figure out how long I could expect the decks to remain viable. I understand the K9 deck is pretty meta and the Darklords is kind of off-meta/low tier.

How long could I feasibly enjoy a $200-$300 deck before it becomes something that can’t be used anymore? How often does the meta get shaken up? Like in Hearthstone, every new expansion is a totally new meta and old cards mostly become obsolete. In Yugioh is it like every new booster pack is a new “expansion”?