If you use outsourced vendor the obvious advantage is that you can start right away and you might even get someone who is borderline qualified (knowledgeable) to sell in your space, however it would be relatively expensive like $7-10K per month ($5-6K would give you part time person). It would also be difficult to coach this person because they would be remote and you would want them to use all their time selling.
Coaching is important because nobody would know your exact space and without coaching you would be wasting MQLs
Hiring of course is difficult but generally the right thing to do. It’s actually cheaper in the long term and much more effective if you spend the time thinking about what skills you need to look for and spend the time training the person ..
As far as skill set for person to hire is concerned, I would recommend pulling from a competitor (larger company in your space) if possible. I have found quite a few SDRs are looking for upside and would be open to transition.