The FATEs are hard to get to in time. They were in Bozja as well. The strategy in Bozja was to hang around in the middle so you were ready to go in the right direction. It was also fairly common for them to spawn in a set order, although I'm not sure it was strictly guaranteed. The strategy in OC is to wait at the camp Aetheryte then port to the aethernet nearest the FATE that spawns.

They should scale up based on how many fought it (or one linked to it) the previous time. The problem is that a different amount of people may be there the next time (more or less), causing it to be either overscaled or underscaled, especially when some people only fight FATEs if it's convenient due to being near a CE or near a quest objective.

If you freeze and glide it's likely due to your game struggling to load things like textures and animations fast enough. This usually addressed by having an SSD to load files faster. However, it can also be caused by having been tabbed out and the game dumping your game memory into a page file, too much RAM being used by other programs, or connection issues.

You can reduce the animations on screen like this:
/bfx self all
/bfx party simple
/bfx other off
/characterconfig > Control Settings > Character > "Effectives While in Motion": Show All
/systemconfig > Graphics Settings > scroll down to Movement Physicks: set all of them to Full

Now you will only see your own animations, or important animations in your party (such as healer bubbles that you should stand in), and characters shouldn't glide.