Was trying to get a rogue level for my ranger, pre-req is supposed to be DEX - 13, but the system seems to be looking for WIS - 13 for every class

Yes, because the prerequisites are taken from both the class(es) you have and the class your are taking.

 Is there a hard requirement that the starting class has to meet all the pre-reqs same as the classes you are multiclassing into?

Yes.

To qualify for a new class, you must meet the ability score prerequisites for both your current class and your new one, as shown in the Multiclassing Prerequisites table.

*emphasis mine.

https://www.dndbeyond.com/sources/basic-rules/customization-options#Prerequisites