If I wanted to use Ethereum to write out things I should never forget, could I add text to a transaction, and if so, how?

Also, I would need to automate it. Is there anyone who could point me what I should point my autistic focus toward, so I could learn to make this little side project?

I'm sick of using cloud services, and I have some things I need to write down so I never forget them, and I like that with Ethereum, it would ostensibly be there forever (I lose everything)

Can it be done? Could I put my essential memory things on a public key, so I can always just look it up, no matter what decade I'm in and what computer I'm on?