Firefox upon launc advised installing updates and then all my desktop flashed. I had no installations planned or done. Is this malware or real?

See the subject. I've been seeing delays in launching for several months. I've run several windows defender malware checks (full and the one where it runs outside of anything brought up). I've reset firefox. I did all this also because I was seeing random ads from a news site from what they were trying to get me to do was install macafee (but it's malware). While I'm not seeing those ads now and I'm suspicious they can from the news site vs. my browser, I'm very aware of anything trying to capture screen scrapes. I'm even considering changing all my passwords as I'm not sure if anything was captured. This morning, firefox upon launch took a long time. Then it said installing updates. My desktop flashed and firefox launched. I have not installed anything or any addons, extensions, etc. So either this was firefox doing an update it needed or it's something else. I'm on windows 10.