No, Avast is not malware. In 2019, Avast’s subsidiary — Jumpshot — was accused of collecting and selling user data, but this has since been shut down. Avast is still good at detecting and removing malware, but there are better antiviruses out there that are more reliable, effective, and trustworthy.
For Windows, Norton 360 is the best choice — it has perfect malware-detection rates, provides an excellent set of extra features, and offers a great overall value. For Mac users, Intego is the best antivirus available on the market, with top malware-detection rates and more features than most other Mac antivirus programs offer.