Blocking 3rd party trackers (default in safari) would mitigate ad tracking.
Using 3rd party Reddit clients would limit ad tracking as well since they don’t load ads and aren’t concerned with engagement metrics recorded client side in their first party app.
Amazon, Google, are cloud providers for lots of websites, they probably don’t track based on this, but your data passes through their networks regardless.
iCloud private relay is still the best option, also reading the websites privacy policy and not using the services while logged in.
This issue is very complex so you have to be willing to compromise if you use these services. Browser fingerprints is another confounding variable.
Amazon, Google do track you and build profiles even when not logged in, however this data is used internally, it’s not being shared with 3rd parties. You can turn off certain aspects of tracking in your account. Advertisers submit their ads to google/Amazon then serve them to you based on relevancy, the advertiser doesn’t get your information specifically, some metadata for analytics. You can read more about their respective privacy policies, but your data is private with them and perhaps law enforcement.
Weather: stick to the stock weather app on iOS, good privacy policy.
Health: Stick to stock health app, Apple takes health privacy very seriously and keeps as much as possible on your device because they don’t want liability.
You will be tracked some regardless for analytics, the key is to not use these services if it’s a concern.
Let’s say you use a VPN, these services know it’s a VPN since it’s typically a data center IP. You only have to mess up once for them to know your residential IP. Residential IPv4 is typically ephemeral, so unless there is other metadata it can’t be linked to a specific person.
These services aren’t really spying on you, you do agree to give this information when you signup for them. There’s plenty of opsec you can do, like perhaps only using tor, but generally if not committing crimes, iCloud private relay is sufficient.