Just…
Don’t let them deceive you;

If you must use deceitful software like Gmail, Whatsapp, Discord, office or whatever, just try your best not to leak your personal data on them, and if you can hinder the tracking, do so.

If you can use other (preferably FOSS) software, do so, there’s plenty of solutions out there and most of them are free, and sometimes selfhost-able.

Google, Meta, Microsoft or whatever corp can lie about security or privacy all they want, but in the end, they only fool themself thinking their monetary practices aren’t obvious and they can fool everyone, trust is a hard thing to earn and they can’t earn it with fraud.

The product mostly show itself, and you have to go around it to know what’s it’s deal, if you prefer to not do so, you can search if any security researcher or analyst did investigate the product; For example Google claims Chrome browser is “safe” and “secure” dispute them giving so much trackable APIs for websites, and having a horrable default permissions, and don’t forget the “Manifest V3” transition just to remove ads (and trackers) blockers like uBlock Origin.
You don’t need solid proof to know what is what.

And then you just type " Foss Chrome Alternatives" or “Private Browsers” on a search engine like DDG where you can find many articles to help you find one (like this) and you’d be done.

Forget about ““Others”” right now, your well-being matters the most.

Yes, but how would you know Meta doesn’t have a copy of your encryption key (ex: when you sign up) and keeps a copy of your encrypted messages somewhere?
AFAIK your encryption key resides as whatsapp’s data folder but since whatsapp is closed-source you can’t guarantee that whatsapp gave the encryption key to Meta’s server at some point when it was created; (or it was created on their servers and sent to your device.)

One would just assume the encryption key is made on your device and never sent to Meta and all the E2EE messages aren’t kept on Meta’s server after they are sent.

Again, Meta is a company that is profiting on targeted advetising and selling user data, how would whatsapp be a free service without any profit?

Also, Here’s someone who saw their whatsapp chat used for targeted ads on them in case you have doubt.

As much as I’d like to favor foss and federated messenger apps, telegram isn’t as much garbage as whatsapp:

1.The client is somewhat open source and have forks like Forkgram, Materialgram and unoffical clients like Telegrand.
2. Telegram isn’t E2EE by default but at least it doesn’t lie about it and have E2EE secret chat when nessesary, that means crucial chats stay on your device and the rest stay on their database recoverable and syncable across devices.
(Yes, whatsapp supposedly is E2EE but we can’t know for sure, it’s closed-source.)
3. You can use telegram as a cloud service with only 2GB per file limit, unlike whatsapp.
(There’s even a third-party app that utilise this as a cloud gallery.)
4. Even tho telegram has ads in large channels, telegram isn’t funded by a greedy big-corp and it doesn’t datamine you, ads are based on the channel’s topic.

Yes, in terms of privacy, telegram isn’t the best option, Signal, Session, XMPP, Matrix, or SimpleX have better privacy features, less linkability and E2EE by default but telegram is very mainstream and got more publicity, making it the whatsapp alternative it advertises itself as-is.
Publicity doesn’t make a better messenger app, but for what it tries to do, it’s adoptable for simple users, doubles as cloud storage and is more secure than the garbage being whatsapp.

Immigrating users to different apps is a headache on it’s own, but if they know of telegram and it’s not privacy invasive, that’s not bad.