You might have incorrect expectations - if you are scraping contact info from LinkedIn and getting any responses at all, you are doing well. 25% connections and 1% interview rates sounds like you are doing great.
Could be that as well. Maybe someone else will chime in with their numbers so I can get a reality check. I'm doing everything almost manually right now so it's not efficient.
"Do things that don't scale" (https://paulgraham.com/ds.html) is probably also fine in the idea finding stage. At least then you are quicker to pivot than if you spend a lot of time optimizing the process and it still allows you to do a more personal approach instead of a copy paste outreach.
