I’ve been meaning to ask whether you have any advice on a related issue. One problem I come across is that I want to (and do) split up the meanings as you suggest, but I worry that the differentiating hint is actually also giving me a massive clue to the meaning of the word.
To take your example of a bright room, I might not remember that あかるい means bright, but may be very confident in the word へや. If there are no / few other cards with the hint へや, it’s quite likely that I’ll just end up seeing へや and making the connection via that rather than actually remembering the meaning of あかるい independently. “Oh yeah, the word about describing a room… as being bright”
So… any tips? is it just about picking good words to use for hints? If the different meanings are used as different parts of speech I try to use that information as my hint, but that’s not often the case.