I’d say try Linux. Ubuntu or Fedora and you’ll realize how much of your computer usage is based out a web browser and it doesn’t matter whether you have a Linux, Mac, or Windows computer

Email you’ll be stuck with some corporate entity that won’t be 100% open source. Running an email server and your emails not being filtered is a pain. I use Proton applications for email, VPN, and Dropbox type service. They have a calendar but hard to beat google calendar

Signal for pretty much texting. I actually have around a dozen people I primarily message through Signal so it’s viable for me

Matrix/Element for something like discord.

Onlyoffice, Libreoffice, or WPS Office instead of MS Office. WPS may not be open source

Browser use Firefox or Firefox forks

Krita, Darktable, GIMP for image editing

KeepassXC for my desktop password manager and whatever is available on Android

Maps you can use Organic Maps

Video editing i use kdenlive