In response to the title: Uncertain, if they follow the recommended method of securing bitcoins should separate them into several non-custodial wallets for a certain amount limit say >5
BTC or (if not) move them regularly to a new wallet.
-snip-
but I'm wondering if it's safe to keep everything in one wallet from one company.
Safe from theft/loss? It depends on how you secure your device, PIN, seeds, and other recovery features.
Safe from tracking? Probably not, even more so if you're a verified user.