It also looks like your flat depth is wrong or you have some other setting wrong (but I agree on more conservative feeds and plunge, at least half the feed rate for plunge). Compared to your preview, your cross hatched texture shows the in both directions, you are too deep, and consequently, too “wide” so every other row is getting the sides cut out of it. So it does one side of a row correctly (call it Row 1), then but at the same time is too wide on the row next to it (Row 2), even though it thinks it is correct. Then when it moves one path over, it cuts the face of Row 3 (that is towards rows 1 and 2) correctly, but it is also too close to Row 2, so it makes Row 2 too small on both sides.
I wouldn’t think it would matter what size V-bit you would use although I would try something steeper, maybe a 60 or 30 deg bit, so that you get “steeper” walls on the textures. Also don’t forget that your V-bit most likely does not come to a point, it has a flat area. The larger the bit, the bigger that flat point will be, which may also cause the issue.
Regarding the wavy lines on the sides, for cutting metal you have to be absolutely sure that your V-wheels are tight, and your drive pulley set screws are tight along with belt tension. Also, I use two wrenches to make sure that the bit is tight in the collar. You can’t tighten it with just one wrench and the button enough. Watched your video, and you are correct that you need some lubricant, which you figured out.