If I had to guess where all this future capital gets put, I would guess that it looks something like the past.

Occasional acquisitions - most recent was $11.6 Billion cash for Alleghany, next up is taking Pilot Company ownership up to 80% and consolidating. Bolt on acquisitions at many of the subsidiaries. Marmon bought a company just recently - aftermarketnews.com - Ap emissions technologies acquired by berkshire hathaways marmon holdings

They don't need $50 Billion acquisitions, they can do a few $5 Billion, a few $15 Billion, etc.. there are plenty of companies in that size range. But who knows, OXY is friendly. Warren also seems to like Celanese, another female-led company that Berkshire has been buying.

BNSF pays out all of their earnings to Berkshire as dividends. Berkshire does still finance acquisitions at Berkshire Hathaway Energy, most recent was National Indemnity funding the pipeline purchases through a special preferred stock that is being rapidly repaid. There are plenty of acquisition candidates for BHE and that is how the company was built after all. Plenty of organic investment opportunities there as well.

Preferred stock financing deals with warrant kickers negotiated privately. (shocker, I know)

An actual bond portfolio for some of the insurance float - the recent interest rate environment made it seem like Berkshire had way more excess cash than it did because Berkshire chose to run the bond portfolio inside the insurance companies with such a short duration that most of it was classified as cash equivalents. This has just recently started to change.

Large cap equity purchases. A recent example is Taiwan Semiconductor. All we know is that it is big enough that it is likely a Warren purchase and that Berkshire held 60,060,880 shares at the end of September 2022. Subsequent to that date, TSM continued much lower and still trades at prices Berkshire was likely buying shares at. Which means Berkshire could own a lot more than 60m TSM shares when we get the next update. Current market value of the TSM stake that we know about (the 9/30/22 shareholdings) is $5.35 Billion. It could be substantially more if he kept buying - and why wouldn't he have kept buying?

Berkshire common share repurchases - the cheaper the better.

The above should be enough for the next team to keep the machine running without reinventing the place. If it ain't broke, it doesn't need fixing.