Well I would say you should know all the skill sets of a BA and be able to speak to each one. A BA, at their core, is someone who can learn about a system (or multiple systems), someone who can work with teams of people from the operations to the technical people and they should know the ecosystem they are working in. These people have to, therefore, have some technical understanding, good technical writing, domain knowledge and teamwork skills. Some places have BAs work as pseudo project managers too...
Some things like technical writing you can learn from a course. Other things make more sense to learn on the job somewhere. All things considered, if you can show these traits you're in good shape.
Nah i know that, not to brush you off and be disrespectful. Im speaking more on tangible skills ie. Learning specific software or certs to add to my portfolio that are worth wild/time/investment. Im getting my masters and plan on tailoring my curriculum around stuff that will keep me relevent, i already work in the industry but it is easy to get comfortable in a gig and become outdated as you are good at what your company does, but may start lacking skillsets that are new/used in the industry but not your job.