Customizing repeating styles and blocks


I hope I can at least explain this properly.
Please keep in mind I’m a Webflow novice and I come from the design side - I only have basic/limited CSS, HTML, Javascript… knowledge. So this may sound stupid for some of you. Even more so I appreciate your advice!

Here it goes…

I’m building a timeline within a history section of a website. See attached image below.
As you can see in the attached image it has two alternating but similar (for lack of better wording “left and right”) blocks. These blocks are repeated and just slightly customized each time (mainly just different copy/content).
I opted for building the first “left” block in a Div Block, copy that Div, then customizing the copied Div Block to build the second “right” block below the first. I would then hold them both together in another Div and repeat the latter combo as many times as needed.
The issue is that altering copied elements alters all the other elements with the same class/name. I went through the trouble and renamed the elements for each copied block but unfortunately it just renames the parent elements.
I’m stuck here!

What is the best way to do this efficiently?
Combo classes? Even then it seems a a lot of busy work for what I was hoping would be an easy templated repetition kind of task.
Whatever the solution, I’d like to prevent unnecessary complicated, messy code that may not hold up well on every browser/device and not be fully responsive.

Thank you for any suggestions!