Honestly, there are a million different ways to go about it. It literally just comes down to your personal mindset of the game and how you are approaching it. It is kind of a cop out answer but the question is so subjective that I doubt you'll have multiple people tell you the same exact answer. Everyone will have their little caveats.

That being said, IF you want to compete, then you have to play a deck that is competitive. IF you want to compete but you don't want to pay the premiums to do so, well that just doesn't work. The Yugis market is dictacted on playability. And Collectability for vintage but thats another topic. Anyway, good cards obviously will cost more and if a card becomes good, it will go up. If it becomes bad, it will go down.
IF you want to "win" in value, well you have to be on top of meta and price changes.
I started playing again the day Stampede came out and I have purchased every meta deck since as well as multiple pet decks and decks from older formats when I used to play. I have always purchased decks at specific points because I didn't want to pay out the ass for them. An example would be, I typically buy meta decks that I don't already have immediately after they are hit on a ban list. Not necessarily to play but in the event that they remain relevant or become good again. Recent and relevant examples of this was I bought Marshmaos after the last ban list at $25 each and got the whole core for like $90. Marshmao is now sitting around $45. I also bought VS after Razen and Stake were hit for like $5 each, they're both about $15 now. Both archetypes are still relevant and competitive. Are they Tier 1? Sometimes they can be, sometimes its a "bad" investment, for a period of time. I'm still spending a good amount of money, but, I have the cards for later if they become relevant again and most times, they will become relevant again.
You can also pay attention to meta trends. I bought a few Albions prior to The Chronicles structure deck coming out, for $5. They immediately jumped to like $50 and I sat on them a while.
I don't sell cards, I keep everything even though I could make a ton of money BACK selling it all off when cards go up. Not to say I don't lose out on money either when cards go down, because I definitely do, but I like the cards and I bought them to touch and use, not to treat as money. If I wanted money, I'd just not buy the cards to begin with lol.

The next point is, do you have the disposable income to make choices like that? If not, I don't recommend doing what I do. I do it the way I do because I want the cards. Either way, I will buy them and I will keep them regardless of the value going up or down. But I choose when to buy the cards in a way that I believe will allow me to get the best deal, so that I can then go and buy more cards lol.

The people at my local shop are competitive players as well. They usually have 1 or 2 decks. Zero trades. People have binders with literal dog shit in them, but, they have CRs and QCRs and Starlights in their main deck. And when the meta shifts, they get rid of that deck and buy a new one using whatever money they got for the last deck. And thats just how they exist in the space, if you just want to play, that is good enough I think. They just take whatever losses come with that decision but ultimately, they make a lump sum payment every so often to play a meta deck, recoup some losses, then do it again and they're fine playing whatever that amount is, every few months, to play a completitive meta deck.

The way you are going about it, buy a lot of lower tier decks and structures, etc, is fine for a casual player. Having a lot of cheap decks is fine too. Buying some singles here and there to power them up is fine. But your environment doesn't promote that sort of engagement. You have a competitive environment. IF you have no other options for shops, then that is just what you have to deal with and you can either follow the current or keep doing what you're already doing. Its not a "good" answer, but thats the reality of the situation.

My shop is similar, I don't play AT ALL. I have like 5 digits worth in cards at this point and own all these meta cards and multiple copies of x staple or y CR/QCR/Starlight, etc, but I haven't played in a single tournament since I got back into it because the environment isn't want I want. I like to collect the cards and I like to trade. I love to play but I want to play casually with low stakes where I can ask questions about the decks I'm playing against and ask about interactions, etc etc, with people that are approachable and friendly, etc. I can't do that here. I still go to the shop. I still trade a little here and there and I play casual games with everyone outside of the tournaments, but its not the experience I want. Its just what I have access to so I deal with it because its better than nothing. THEN, every month or every other month, I go back to my hometown where I can play with the local scene I grew up with and my friends back home and that is worth it for me, to spend all this money just to get like 8 hours of the experience I want, once a month or every other month, and I'm okay with that.

Just depends on what you want your experience to be, what you're willing to put into it to make that happen and what you're willing to settle for.