Exiting the Mac
Switching from macOS to Linux isn't hard. All you need is a PC, an ISO for the Omarchy or Omakub underlying distro, and about 20 minutes to do the install. What can be hard is getting out of the Mac's ecosystem! It's not the software that gets you, it's the services.
So here's a list of replacements that I've enjoyed since switching:
iCloud Files to Dropbox
Steve Jobs famously tried to buy Dropbox before launching his own file sharing service with iCloud. He claimed that Dropbox was just a feature, and they'd be foolish not to sell him their company for his low-ball offer. Good thing they didn't!
Dropbox has been storing my files since launching in 2007, and it's never let me down. It's not tied to a single platform either. There are clients for Mac, Linux, Windows, iOS, Android, and web. It's excellent, worth paying for, and a great alternative to iCloud Files.
Dropbox is an optional install on Omakub and a default install on Omarchy.
Email + Calendar to HEY
Now this is going to be biased, because I made HEY together with my team at 37signals. So of course I'm going to recommend it! HEY is a complete rethink of what an email and calendar service + client should be. It's not just an app that connects to a big tech provider. It's full service, and I'd be honored if you'd check it out.
Now there are plenty of options in this space. The 800-lbs gorilla is of course Gmail from Google, and if you're already using that, there's nothing to migrate. All of Google's tooling is web native, so works great on Linux.
Both Omakub and Omarchy have web app shortcuts to HEY. (If you don't want to use it, you can run web2app-remove HEY).
Photos to Google Photos
While you could store your images on Dropbox, it's nicer to have a fully integrated photo solution, and Google Photos is an easy answer. They have an iOS client that makes it trivial to upload your existing Photos library to their servers, and then you can use photos.google.com to access it.
On both Omarchy and Omakub, you can turn that into a web app you can launch with the app launcher (Super + Space) by running:
web2app 'Google Photos' https://photos.google.com/ https://cdn.jsdelivr.net/gh/homarr-labs/dashboard-icons/png/google-photos.png
Notes to Obsidian
Obsidian is an excellent free note taking app that stores all data in flat Markdown-formatted files. You can put these files in a folder on Dropbox (that's what I do!) or you can pay for the Obsidian sync service, if you need access to your notes on your mobile phone. It's great.
Obsidian is installed by default on both Omarchy and Omakub.
iMovie/FinalCut/Premiere to Kdenlive
Kdenlive is an excellent timeline-based video editor that I've been using for quite a while to do all my screencasts and introduction videos. It's got all the basics, it's fast, it looks pretty good, and the output is ace.
I use OBS Studio to record both screencasts and full camera segments that are then put into Kdenlive to compose the final videos. It's an excellent one-two punch for anyone wishing to publish video on the internet.
On Omakub, Kdenlive and OBS Studio are optional extra installs. On Omarchy, they're both installed by default.
Messenger to Signal + WhatsApp + Google RCS
BUT WHAT ABOUT THE GREEN BUBBLES??? Yes, Apple has cornered the psychology of the out-group with their Messenger design. It's deviously clever!
Yet here you are. Thinking about switching from the Mac to Linux. You're a bit of a renegade, are you not? A bit of a free thinker, yeah? Not the type of person that's going to be held in captivity by the color of your messaging bubbles!
Glad we cleared that up. Because messaging on Linux is great with both Signal and WhatsApp. That's what I've been using. Signal has a native client, WhatsApp runs as a web app. Both of them use first-grade encryption, work on every platform under the sun, and are included by default with Omarchy and Omakub.
Oh, and if you're on Android, you can also get your SMS/RCS messages by using https://messages.google.com/web/conversations. (Which you can turn into a web app with web2app).
Keychain to 1password
You are using a password manager, are you not? Because if you're not, you really must. Password hacks are being announced left and right on the daily. You need a password manager! But if you've just been going with the default on the Mac, you're using Keychain. A great gross-platform alternative is 1password. It's included by default with Omarchy and Omakub.