Recently, I tried the ff. free products, with as many notifications for upgrade ads disabled, and anything like silent mode and game mode enabled:
Kaspersky Security Cloud - updates to Free Antivirus; popups for upgrades still show up; also, sometimes some forum pages I revisit don't load fully, even though I keep refreshing, clearing the cache, and turning off any adblockers (I use Adguard for Desktop, and experimented with turning off and tweaking browsing security, DNS protection, stealth mode, the WFP driver, etc., after being told that conflict between it and AVs may take place);
Bitdefender Free - no popups, but the behavior's weird; for example, in some places downloading the installer can be slow (it speeds up if I use a VPN), it takes a while for the icon in the system tray to show up after the AV is updated, and some forum pages I revisit are not loaded fully even after I keep clearing the cache (same problem as above); I'm not sure if there's some conflict with Adguard;
Avast Free - popup for upgrades now show up; has an annoying feature where it shows a blue dot in its system tray icon to indicate that a site has been blocked, but it's not a deal breaker;
Avast One - I think there were no popups, but many features not needed can't be disabled; it scores the lowest in Novabench, but not as bad as Windows Security; also, oh my eyes...no dark mode;
AVG - OK so far, but I don't know if popups will eventually appear, and a similar issue as Avast concerning the blue dot;
Given that, I've been using Avast Free, but am re-trying AVG because of the popups.
As an alternative to those two, maybe I can just use uBlock Origin for browsers, and then just use Adguard to block ads in apps like Ferdium, which has no ad blockers.