TS3, Steam, and system requirements questions!

Kinda dumb question but I have been a disc-only player for these games most of my life and just made the transition to Steam after TS4 was purchased for me as a gift. I don’t really like it after a couple weeks of play, but I see that TS3 is available in a big bundle and want to jump back in. However, I’m worried about system requirements.

I have TS3 + several expansions on discs that I used to play no problem but I ended up uninstalling them when I bought a new computer ~4 years ago because the colours were off and it had something to do with the graphics card being too new (I think? This was a few years ago now and I think that was problem). I struggled to get it fixed and gave up, sadly.

If I purchase/download the games through Steam would this issue possibly still happen or would it being a digital copy make a difference? I assume there are workarounds for whatever issue I had since people are running much older versions of the game on new computers but don’t want to make a huge purchase and end up not being able to use it!