Pet Collector, an R10 badge, requires 250 orange badge bits and 100 red badge bits. Assuming you’ve got a double drop going for campaigns, that’s 500 raids for the orange bits at 6 stamina per raid, and 200 raids for the red bits at 14 stamina per raid, or a total of 5800 stamina, just for the badges you can’t get from diamond crates.
There’s also the fact that the badges you get from diamond crates are random; a badge that you have 5000 bits for is just as likely to come from a crate as a badge you’re perpetually out of. Even if you get lots of badges that you’re short of, you may not get enough of the badges you need for the heroes you’re wanting to promote.
Diamond crates are good, but I don’t see how you can promote your heroes just using what you get from them. If you have any advice on how to get sufficient R6+ badges to promote my top 20 heroes without buying stamina deals occasionally, please tell me, because I’d love to play this game more efficiently.