I have used a PiHole ever since I learned that LittleSnitch resolves DNS queries (to IP) before the dialog prompts whether to Allow/Deny a connection to the unlisted host. It is an added bonus that I can route my entire subnet to the local PiHole, which prevents rogue software/OS/devices/phones from initiating undesired connections. If you know how to make a few simple IPfilter rules, you can even stop hard-coded devices (e.g. smart TVs) from phoning home with internal DNS IP addresses — all you have to do is capture all DNS queries, IPs included.
Simply blocking pagead2.google.com and googlesyndicate.com will remove 50%+ of website advertising. ReGex rules allow for ads.* (etc.), and these rules apply on your entire local network. For an added bonus, you can then use your local PiHole to resolve DNS queries remotely (e.g. from your phone) — just all around an incredible product!
Ublock will get you 99% of the way there tho unless for some reason you're stuck using chrome. Then usually brave or vivaldi will fill in the gap. Avoid chrome always.
I just tested "macbook pro for sale" without and without ublock and they disappeared when I turned it on. Are you able to produce an ad in a search result right now with ublock enabled?
I don't use voice at all other than "set an alarm for ____" but firefox search works just fine and ublock origin works great on it. It's a little slower than chrome but you would never notice it unless you're doing ms level tests on it.
For searching in Google? I use Google with the Firefox mobile browser, yes. I also don't use voice commands on any platform, just transcription GBoard and I've had no issues.
ublock origin seems to do fine.
Unless you are suggesting that the ad-ladden SEO'd pages are their real product?