CAMT (Corporate AMT has no effect on Berkshire's taxes in 2024. From the latest 10-Q (this remained the same compared to Q1):
We do not expect to incur CAMT liability in 2024.

I have assumed that to be the case. But there could be complexities that I'm unaware of.

And as an aside, the Q1 report was penned in the latter part of April, so that expectation could be deemed to be as of that date. I imagine some decent amount of stock sales (Apple) had already taken place by then. So, though I don't necessarily believe it, that comment could have taken into account a lot of sales: if enough of the anticipated 2024 taxable profits had already been realized taxable profits, then it would create the expectation that the AMT wouldn't apply. By March 31 there was already $14.2bn in taxable realized profits, which moves things in the direction of ensuring that all taxes on gains would be taxes on realized gains.

FWIW, Berkshire's cash tax paid (as opposed to booked tax liability) in recent profitable years has been less than 15% of GAAP earnings before tax.
12.58% in 2023, 13.81% in 2021. So on a very naive reading of things, some CAMT would have been payable.

Jim