Luckily you can play this game and enjoy it without having to do that.
I’m a long term player and I have bought one crystal pack, which gave me 10 Home One shards. I bought the pack knowing that I needed those minimum 10 shards to reach 7* a month early. Any extra would have been a welcome bonus (didn’t happen).
Simple solution: when gauging the value of those packs assume you will get the minimum. If it’s worth it to you, then go for it. That way if you get the minimum you will be ok with it, and any extra is a bonus.