It are somewhat seperate problems. But let's begin with ad's, tracking and malware/bots/whatever uses a domainname. You have two different options SaaS and self

It are somewhat seperate problems. But let's begin with ad's, tracking and malware/bots/whatever uses a domainname. You have two different options SaaS and selfhosted. It's a matter of opinion but I would say PiHole (selfhosted) or NextDNS (SaaS) a no cost SaaS would be using the AdGuard DNS servers in your router instead of the ones of your ISP. Personally I use NextDNS, it's robust and thanks to the options I can tweak it to my needs without having to upgrade / update stuff. The second part, keeping my network secure is a bit more involved, it can mean anything from simply having different wireless networks for different purposes (IOT, video surveillance and guests are common) to packet inspection and intrusion detection. Mostly, use the seperate wireless network strategy and forget about the rest, the maintenance is too high and the gain too low for personal networks.