Free and simple software
Free software is free as in price, and as in freedom (you are free to inspect and modify the source code for your need). These are usually more secure, as people can audit the code. Simple software won’t get in your way, instead, the software works as they should, and they are not bloated, which run faster!
Window manager
First bloatware to remove is the desktop environment. Using window manager not only reduces the use of system resources, it also improves your productivity. A tiling window manager will automatically tile windows for you, so that they won’t overlap each other. Think about it, when would you need to stack windows on top of each other. Using tiling window manager just make more sense. There is a huge list of window managers, below are those I used and would like to recommend.
Office suite
Office suite will sometimes exhibit unexpected behaviour, like page breaking, pictures covering texts, or items just completely dislocated when you open slides on another computer. These are often a headache to ‘debug’, because you don’t receive any error message.
Word replacement
There are a bunch of software that can compile text into pdf. For example latex, typst and groff/roff. I always use latex as this is wildly adopted, and is very powerful. For taking simple notes, just use markdown, it is readable even without markdown viewer.
Spread Sheets replacement
There is not much reason to use a spread sheets programme, manipulation of numbers can be done much faster with python pandas reading csv. MATLAB and R exist as well.
Slides replacement
Latex beamer is simple, easy to use, and won’t get in your way. I haven’t used PowerPoints since I started using latex beamer. Latex beamer is compatible with latex. So, after finished typing a report in latex, I can just copy and paste stuff from report to slides, things like images, captions, math equations.
Text editor
Even if you are not a programmer like me, you will still be benefited from learning vim. The keybindings allows you to manipulate texts faster than ever. It is also very customisable that I can’t really find another text editor that comes close to it. You can create custom functions to streamline your work. I use neovim to write everything, including latex (I have custom functions to create figures, tables, and so on), latex beamer, and markdown.
Vim motions can also be used outside of Vim! For example, vimium allows you to browser the web with vim keys, zathura for pdf, imv for images, and many others.