But…
We have just started the year and we are already being invaded by these creatures?
I’m sure the troll will again storm in here and crap all over and help no one, but I will share instructions anyway.
So to get the old style yellow notifications much more readable in 240p super res modes, I went for a super wide font in TTF format, like the following:
I connected via WinSCP to access root folders: https://wiki.recalbox.com/fr/tutorials/system/access/network-access-winscp
I navigate to:
/usr/share/fonts/truetype
I enable write access by sending a custom command within WinSCP:
mount -o remount,rw /
I copy the TTF font there.
Then in game, open retroarch with Hotkey + B or bottom face button. Main menu, Settings, OnScreen Display, Notifications. Turn off the widgets. You can then select a font, select a size and position. You can go to Notification Visibility and turn on frame rate or something so you have a live demo of your size changes. When you like the size, go back to the main menu, Configuration File, Save Current Configuration. That seems to apply the new font settings for all emulators.
I’m now happy with my legible notifications and can enjoy achievements, despite missing out on the cool widget graphics each one has. At least you can see them on the official site.
@Mozgus You’re welcome.
If you have any doubts, feel free to ask, I have infinite patience for limited people.
You provided zero assistance and failed miserably, and everyone can see that. No fonts provided with retroarch fixed the issue. Only my guide can help people. You are a nuisance.
I’m blushing. 
Please, there is no need for so much flattery.
You are welcome here.