Beachhouse ding repair in Oceanside Ca does the best ding repair I’ve ever seen. If I was going to have them filled, that’s who I’d use without a doubt. He could probably do some kind of coverup to make the repair invisible. He’s a magician.
Big ones like that are a bummer. I tend to agree that attempting to fix them will often lead to more harm/work/money than it will any appreciable difference in the surfing experience. If they start to bubble then it's time to think about cutting them out, filling the space, and re-glassing the area.
Get roven rope and do the same thing glassers do when they glass on fins resulting in transparent look, and the roven will bond well with the surface. But if you don’t saturate the ropes 100% you can end up with hair lines of un-wet fibers. Resin only is bad as it won’t bond well and easy to crack. I don’t understand filling the dents can do harm to the board lol won’t add significant weight either, sounds like someone just needed some holiday break as it seems like a bunch of work
Marine filler (waterproof) has worked really well on my 10' Pavel eagle that had numerous dents on the bottom. Added a negligible amount of weight and much easier on my eye and psyche than the dents. I hit them with various colors of spray paint for an abstract look. No taking water or repair degradation and easy to sand. Kirk Putnam often repairs old Liddles this way.
On a few much nicer condition boards, @ridgeline handled the repair / fill properly with actual resin and the final result was almost unnoticeable.