It is possible to mod the difficulty settings, but not easily unless you have the tools.

If you browse the CnCRemastered installation folder, in the Data subfolder there's an archive file called CONFIG.MEG. Packed inside the archive is a file DATA\XML\CNCRULES.XML.

Inside CNCRULES.XML, look for the section The modifiers for Red Alert are also in the file, under the RA name. For the correct game, look for the relevant difficulty key (Easy, Normal, or Hard)

The stats are mostly self-explanatory, and work as multipliers. Possible stats to change are speed, build time, armor (damage taken), rate of fire, and cost.

You can fine tune the values however you want. Editing the MEG file isn't very intuitive though. If you need help with that, I can describe the steps.

Thanks a lot, will look into it!

(might give Normal another try or two but generally looking for a difficulty level where I feel challenged but still having fun, RA1's "normal" is more to my taste)