It appears that values as high as "1.999999" work for "Model Draw Distance"/"LODDistanceScale". The display quality settings can be customized. I modified these setting to be triggered when the graphics options are set to max (high/ultra depending on the setting). In my GraphicsConfigurationOverride.xml file I have these overrides (I also make the same changes in the main GraphicsConfiguration.xml file to the relevant sections (because one or more of the overrides need to be in there - particularly the GalaxyMap ones I think). These recommendations were made by DisillusionedBook.
They cause no FPS hits during ship and on foot exploring gameplay and see a huge improvement to the milkyway skybox, planet texture quality and anecdotally see far less terrain LOD morphing on surfaces either on approach or driving/flying low over the surface. The following should only be implemented if you have a decent newer card with 8GB+ VRAM - and note my setup is only 2560x1080 with 75hz monitor, RX 6800 card - If you run ED at 4K and are already struggling maybe these will not be any benefit for you. You can use 8192 or even 16384 for screen shots of planets, but I don't consider them suitable for general play. Note that I recommend against using texture resolutions past 4096 as you will get progressively more noticeable texture pop-in around complex areas like starports, irrespective of how much video memory you have. If you want to keep things simple you can paste this into your "GraphicsConfigurationOverride.xml" file (normally located in %LocalAppData%\Frontier Developments\Elite Dangerous\Options\Graphics\): You can increase the texture resolution of planets, the galaxy background and the environment map. 8 Graphic Tweaks, Dreamscape Feeling & alii.