Changing your hosts file helps but it would only block hostnames primarily used for ads and trackers - it wouldn't address those trackers and ads loaded from hostnames shared with actual content. The more sophisticated sites will proxy their tracking and ads through their main app:
E.g. www.cnn.com/ads.js
I prefer having multiple layers just in case anything drops off:
1. VPN DNS / AdGuard local cached DNS
2. uBlock Origin
It's like wearing two condoms (but it feels better than natural).
Hosts alone won't solve many ads. Plenty of companies include their own annoying content from their own domains. uBlock lets you get far more fine grained, blocking specific paths.
More concerning is that social fixer was turned off: https://socialfixer.com/
MFGA Make Facebook Great again ;-)