I'd want to have two radio button on a screen flow. If I select one of these, I want to open a salesforce page(a record page or a related list of that record). Instead if a select the other, I want to go next with the flow. It's possible without using LWC? Thanks.
No, it is not possible without lwc, but you can try to search appexchange. I can imagine this is a common problem that can be solved by a package.
For example this one looks like having just that: https://appexchange.salesforce.com/listingDetail?listingId=a0N3A00000FvN3wUAF&tab=e