Diochan A1

I have just gotten Diochan. In the process I did some pity manipulation to get two more legendaries. Not the best though. So I only have about 20 summons left and getting Diochan a second time in the next four days would be a serious stroke of luck.

However I really really want her A1. It seems really good. So my other option is a legendary soul stone. But they seem really hard to get. Is their any way to acquire a legendary soul stone within a reasonable timeframe?