This game is unbelievably annoying right now. It's very polished, looks great, and is fun even with all the gripes I have with it. The main issue is that it switches instantly, to a completely unknown color, at a random time + the punishing nature of the lives. If it didn't switch at all, I bet I could go on forever, so my final score is merely based on how lucky I got with those switches.
If you would show a timer until it switches, that would mean that you'd be able to correctly or incorrectly assess how many more layers of the same color you can grab. I think you already have a grace period after each switch, which kinda acts in the same way right, like if you know it's been a while since the last switch you'll want to play less risky, but sometimes that's just impossible as there is not always an empty space.
You could also devide the side bar into sections and make it dependent on when you grab the bottom color of the section when it shifts down. So if it starts with Green at the bottom then Pink, White above, you'd grab green first, it gets deleted, so now it is Pink, White, White, and then you need to grab pink.
Lastly another option is you could add a brief transition period for each switch, where both colors are allowed to be collected for 0.2 seconds