I think either approach is fine IF you have the time to work on the suggested changes. If you don't have the time or aren't committed to seeing the changes through, I wouldn't bother with either. Golf is a pain in the ass in this way.
Lessons with pros these days will/can involve video if you want. If you're struggling with your game, most likely the fix is something reasonably obvious and probably won't require video analysis. My feeling is that video is for nitpicking.....not anything major.
Everyone takes lessons or has someone look at their swing occasionally. Tour players on down to beginners.
Keep focusing on GPA.......grip, posture, address. With grip being the most important of the three.
Do nothing for the next two weeks except hit balls with a correct grip (don't worry about swingplane, impact, or where the ball goes). The correct grip may feel entirely awkward at first. There will most likely be a few shanks. Don't worry--you'll get used to it pretty quickly. This past winter I had to correct my grip....some bad habits crept in over 30 years. It happens.
Once you've got a correct grip, I'd go see a pro for a lesson. I imagine your slice is pretty easily corrected. Stu Ingraham was/is? a very good playing club pro in the Philly area. I don't know anything about him as a teacher. There are a ton of clubs in the area and most are willing to take your money in the form of a golf lesson. Playing lessons are also cool---easy way to get on private courses.
Stay the course. It sounds like you're committed. If you are, your game will improve. And golf becomes more fun.