As clients upgrade, messages will automatically be delivered using sealed sender whenever possible. Users can enable an optional status icon that will be displayed in the detailed information view for a message to indicate when this happens. These protocol changes are an incremental step, and we are continuing to work on improvements to Signal’s metadata resistance. In particular, additional resistance to traffic correlation via timing attacks and IP addresses are areas of ongoing development. https://signal.org/blog/sealed-sender

In reading about the Sealed Sender protocol, as I understand, it redacts whom you've contacted. However, the metadata does include timestamps. I have no dog in this hunt as 99% of my messages are whispered into someone's ear. Still, one must implicitly trust the receiver of such whispered messages. I honestly don't care what app you use. Those choices are ultimately yours and yours alone and hopefully dependent on who you entrust with your data. This is just an interesting dissection of Signal and privacy/anonymity for the muse.

In the end, we all trust some entity whether it be your ISP who has your bank account info and residential address and can tell when you're downloading 150 gigs of Linux distros overnight even with a VPN, a bank with every last transaction you authorize, the time/date, or government to which we pay income taxes who has pretty much all the info they would need to show up at your doorstep. If your threat model precludes all the above, I would recommend whispering and disconnecting from society. I honestly do not see any other way.