Arabia stamp/series ID help?

Hello! Repost bc formatting was messed up haha.

Unfortunately, I’m from the USA. Came to the subreddit to ask for some input on a piece of Arabia dishware?

I went thrifting today, saw this piece, felt like I had to get it, so I got it. I noticed in the store the stamp on the bottom was unique, but didn’t look into anything until after I got home. And I’ve gotta say, I’m quite lost and very intrigued.

I got the most info from a post/comment here

What I’ve gathered so far:

—Arabia (of Finland?) is some pretty cool stuff. People collect old pieces/sets.

—are Arabia’s collectibles any type of equivalent to the USA’s Correlle/Corningware thing?

——>…except Arabia is much older, and people in the USA appear to collect Arabia pieces too. Do y’all collect Correlle or Pyrex or Corningware lol?

I’m not sure which series I have? The chart linked in the comment I linked doesn’t have this exact stamp lol. I’ve determined it’s Arabia (of Finland/Made in Finland) Landscape Blue pattern. But I’ve seen the same pattern with a different stamp, so I’m just confused about everything Arabia and everything dishware right now.

I promise I’m gonna restore her glory (all the staining looks like it should come off)—just wanted to snap some quick pics for reference.
…With that though, should I use/not use anything specific to clean it?