I've only ever used a single r-gatcha at a time. after a couple dozen times or so I got both R and SR card at once.

since then I've gotten the R card 5 or 6 more times and the SR once more.

but for some reason it took several weeks before I final got the pink card. just in time too, I saw a message saying they'll be swapping out the limited cards soon?

luckily this last event has given tons of R-gatcha cards, so I'm all stocked up.