ı miss old avast one
First, I’m an Avast user and not an Avast Team member and I don’t use the Avast One product. So I can’t speak from personal experience of the Avast One product.
Strange given your User Name, SAVEAVG ?
However, in general for all antivirus programs the following would still be correct.
You don’t mention what program version and build number (you are planning to use), I don’t think anyone can hazard even a guess.
Like any Antivirus program, older versions don’t have the latest program updates which could give better protection, or have fixed bugs/issues, etc.