How to disable shortcuts like Ctrl-A, Ctrl-F, Ctrl-F etc.?

What Mac model and year are your running?

What system are you running?

What app are these shortcuts in?

And download and run Etrecheck. Etrecheck is a diagnostic tool that was developed by one of the most respected users here in the ASC and recommended by Apple Support  to provide a snapshot of the system and help identify the more obvious culprits that can adversely affect a Mac's performance.

IMPORTANT:

Before running Etrecheck assign Full Disk Access to Etrecheck in the Etrecheck's Privacy preference pane so that it can get additional information from the Console and log files for the report:

Also click and read the About info to further permit full disk access.

Copy the report

and use the Additional Text button to include the report in your reply.

Then we can examine the report and see if we can determine what might be causing the problem.

Consider going to system preferences > keyboard > keyboard > modifier keys and setting Control to "no action".

Thanks for pointing out the existence of these shortcuts... I was unaware of them.

What language with special letters is this? What is the keyboard layout?

I would not expect those to use the control key; the ones that I know all use other modifiers, notably the Option key.

I type in Portuguese every day, on a US keyboard, so I use several shortcuts like option-E, option-N, etc.

Occasionally I have accidentally pressed control-E, for example, or even command-E, but for me this would not justify deactivating those shortcuts. I can understand that the one you mentioned are some that you may never want to use, but as far as I can tell there is no way to disable them. I imagine it is baked into the text editing frameworks that are used by most applications.

You can let Apple know via feedback: https://www.apple.com/feedback