This is a totally reasonable approach. Thought I'd throw in my method for this as another option.
I hold the club sticking straight away from belt buckle or so, parallel to the ground, with my right hand. Then, with my hand splayed out a bit (not crazy stretch or anything, but not fingers touching) and flat, I choose an angle to hold my left hand, place the handle in the "right" position, so resting on the middle section of my pointer finger, resting on or a touch towards the wrist from the bottom knuckle of the pinkie finger. Then wrap the fingers onto the handle, then roll the hand towards the handle to a comfortable spot.
For me this method gives a consistent grip, and I can control strong/weak just by the angle of my left hand before I place the handle. If my left hand plane is perpendicular to the ground, I'll get a super strong grip, too strong. With the left hand plane parallel to the ground, I'll get a weak grip, probably too weak, though for me I don't think it ends up as overly weak as the perpendicular way ends up over strong.
If I have time tonight maybe I'll take some pics to make this clearer...
I've always felt this way too, but I've often wondered if more knowledgable players or instructors also liked to see the full speed clips to get a feel for the dynamics of the swing. Like, maybe at full speed you can get a feel for the dynamics and athletic motions a player is trying to use that a player is trying to use that wouldn't be obvious at slow speed. Maybe that might help an instructor decide which things are a priority, or which path or feel or drill towards fixing something is most likely to succeed with that player?
I suppose you're saying that's not true, at least not for you? Like, you get all of that from the slo-mo? Or that might be useful for an instructor of tour players but the shit we've all got wrong with our swings is so basic that it's not needed? Something else?
Like I said… your tempo is probably too slow if you can't get a 30-footer to the hole on slow greens.
You're not hitting a lot of greens, so even two- and three-putting that often is not a great sign. You're not often putting from 40 feet away like some people who hit more greens. You're putting after a chip or a pitch shot more often, and those tend to be shorter putts.
Start a Member Swing topic or post video of yourself hitting long putts to it if you have one already.