In fact, buying a billion on highs is offset by buying a billion at the very beginning of the pump. In general, if you look at this chart, you can see a clear buying strategy, they buy little during strong market movements (whether it be an increase or a fall) and make large purchases during price consolidations.
I tend to disagree here.
I think they are buying every month, roughly, with their excess cash reserves.
They are doing the bigger purchases via Debit Issuing or their ATM facility.
It looks like they are following a pattern, basically because the price has been trending up since they bought their first stash.
Just remember what Michael Saylor once tweeted:
https://twitter.com/michael_saylor/status/1440302444752244736?s=21