What’s the correlation between BRK price and how it’s AAPL holding affects it?

The other day when most tech stock rallied and ended the day in green, BRK ended in red going down a few percent.

This got me thinking, I read some comments on here going on about “if you’re holding VOO and QQQ, there’s no point buying AAPL because you’re already exposed”. I’m like hm, ok, but what I witnessed the other day with BRK price going down it got my wondering as if the AAPL holding for BRK doesn’t affect it at all, I understand they are a single company that’s a conglomerate but now I’m starting to think if I own BRK with the hopes of feeling like “holding a share in AAPL” in reality if this happens, I should probabaly buy AAPL aswell