Can I (and should I) link two lists together?

I have a list showing various risk topics. For each risk, the user should be able to add one or several actions/tasks to be followed up. Can I create two separate lists, and link them dynamically together?

Alternative 1:

Keep everything in the same list:

Cons: the list may become quite cluttered with many columns. And it's only possible to add one task per topic/row.

Alternative 2:

Create two separate lists; one for the risk topics, and one for all tasks. I think this would be the best option for my purpose, but:

• Can I somehow link these two lists together?
• Can I create a "Add new task" column with a button link (similiar to the buttons you can create for running a flow)
• Can I create a column that shows all tasks connected to each topic (and vica versa)

I guess what I'm really trying to do is create a sort of relationship link between the two lists, similiar to what you can do with Microsoft Access and Power BI.