I can swear most of the time you are running around spamming umbral soul and trying to keep alive while juggling your 15-sec timer that if run out you need to spend about 10 to 8 seconds starting the rotation again
nope

you can easily drop the astral fire faze if you cast an instant lightning ... in high-end fights, even the best BLMs cant keep with the boss attacks and mechanics and maintain a real focus on the astral fire faze at the same time
again, just no. with 2000+ hours in blm practice you should be able to execute the rotation (which is incredibly straightforward too) without having to look at your AF/UI timer too much. you can easily utilize thundercloud procs/firestarter procs/xenoglossy for movement purposes, granted you're familiar with the fight. try to find VODs or study logs of high-level players to see how they manage to keep uptime, but please dont spread outright lies like "even the best BLMs cant keep with the boss attacks and mechanics". BLM as it stands has a ton of movement options, and you can now refresh thunder ANYWHERE in your rotation.