Hi! Even though your Livesplit is located in a potentially obstructive place on the screen, the version number at the end is still recognizable (and completely visible as it scrolls in from the right), so this is verifiable. You should definitely move Livesplit to the top right of the screen for the future, though, to prevent the version number and autosave icon from being blocked. If you have any questions about the rules, always feel free to ask a moderator or verifier through SRC direct messages or discord DMs; we're here to help. Congratulations on the PB!
Short answer is lack of interest/runs; categories won't get added to the boards unless there is active interest. For a bit more detail, "low%" can mean several different things. If low% is defined as no collectibles, then you're just running any% with very small variations, which doesn't warrant another leaderboard. If low% is defined as minimum usage of x movement technique, things get complicated. As Cursed said, grabless is on category extensions, and minimum dashes/jumps/ground jumps/etc do exist in theory and have been TASed, but RTA speedruns of those categories are extremely problematic. For one, if a new dash or jump is saved anywhere in the run, then all previous runs would be invalidated, resulting in random leaderboard wipes that would be a giant headache for the mods and verifiers. Also, many dash/jump saves that are humanly possible are extremely precise and/or inconsistent, but they would have to be included in a low% run, making the category more frustrating than fun. Some random ILs have been run RTA with various restrictions, but because of the factors listed above there isn't a board.
with regards to above if you can get a few people to run it then it'll most likely be added, a similar thing happened recently with mirrored ARB