You made it pretty far so I assume you already know the strategy, voltorb flip is addictive man sometimes I put on my favorite game corner remix and just vibe and play it for 30 minutes.
yeah I know, I played it for like 3 hours on and off after accidentally clicking on one of your signature links (which I didn't know were link before then). I didn't mean to play it for that long but I wanted to get to the last level and kept telling myself I'd get it on the next attempt.
Thing is voltorb flip was a casino game, its like minesweeper mixed with picross, there is strategy but its still inherently luck based and you're gonna deal with dumb probabilities which makes getting level 7 pretty tough (never done it myself). You have to grind here a lot if you want to get any of the prizes from the casino in HGSS because they removed the ability to buy coins when they removed the slot machines,