I think the valuation of small companies is not so attractive now. Berkshire used to talk about "bolt-on" acquisitions, but they haven't since 2021. These might be of a similar size to what you're writing about. In the 2018 report they only released per-year totals for the previous three years, stating "we do not believe that these acquisitions are material, individually or in the aggregate to our Consolidated Financial Statements" Except Berkshire did mention a $2.5 Billion purchase of an insurer bolted on to National Indemnity.

I don't know to what extend most acquisitions were discussed when they happened but Buffett didn't cover them much in the Annual Report.
2016: $1.4 B total
2017: $2.7 B total
2018: A $2.5 billion purchase of Medical Liability Mutual Insurance Company, $1 B total among various.
2018 to 2021: "several smaller-sized business acquisitions"

I would think any acquisition smaller than $2 Billion since 2021 won't get mentioned by name.