The amount of feature breadcrumb quests just to unlock a log or some dungeon hard mode that they dump on you at level 50 is too damn high. I feel like I'm playing an ubisoft game with all the feature quest markers that keep popping up. Can I safely skip all this stuff for now or should I just get all the unlocking out of the way?
It's worth unlocking at least 2 dungeons(any of them will do) for the 50/60 queue to get poetics. Maybe also the first 2 crystal tower 24man dungeons, for the alliance roulette for more poetics. Other than that, you can skip all the dungeons until you feel like doing them to see them. You should unlock other features generally speaking though, logs and such. Using this
Progression and Level Locked Content – Gamer Escape stuff that you should definitely unlock:
Glamours at 15, technically not needed but fuck looking like a clown, especially glamour plates combined with hall of novice gear to look like a proper character.
Retainers, unlocked automatically from MSQ but hire some, they're like your bank
Retainer ventures, unlock these whenever, you won't be able to get too many ventures early on but once you have some you want to spam ventures to level your retainers so you can make money with them
Palace of the Dead, if you're planning on leveling alts you'll want that unlocked but you can just do that once you start lvling the alt
Chocobo mount and combat companion, mount is obvious but unlocking the combat one and always carrying greens to summon it. Especially make sure to do the 2 weeklies in the challenge log for it(kill 100monsters with chocobo out) to feed it xp, it's very useful for soloing FATEs and shit, get 4 heal and max attack first.
Unlock adventurer squadrons when you reach high enough rank with your GC. Won't be at level but they're good to unlock early so you can send them on missions and recruit more as you do your weekly challenge log
That's really it for ARR stuff to unlock that's important. You will want to do stuff like materia melding eventually, desynthing, gold saucer and so on but most of that stuff is optional/not important.
Mostly while leveling, you want to make sure to get your GC ranks up(this can be a pain the first few ranks until you unlock deliveries, I recommend leveling a tank to 16 to do leveling roulette with tank bonus a few times). Once you have deliveries just drop all your dungeon gear into it and you'll get up the ranks in no time at all, make sure to complete the GC log(one time only per character, unlike class log) and the quests there, although technically, it's fine to wait as long as you're not wasting GC seals.
You'll also have to unlock the main 3 primals hard mode, which involves clearing them, as part of the 2.5MSQ. So you can do that when you feel like it, it's pretty annoying, have to go to Walking Sands(the one in Vesper Bay), talk to one of Scion, then run all the way to the primal aetheryte(like in Nathalan for Garuda, Umgaro for Titan and Zaharak for Ifrit) to unlock it, then you have to fight it to get the next quest in Walking Sands and so on. Other dungeons needed for the MSQ are unlocked as part of the MSQ, the other notable exception is in 2.1 or so, you need to do The Sunken Temple of Qarn, the 35 dungeon, quests is in Vesper Bay and have to run to the dungeon entrance east of Little Ala Mhigo(have to go there even if you already unlocked the dungeon to progress the quest).
Also worth noting UI wise, personally I just grabbed all the breadcrumb quests, then opened the log and hid them(click on the tick box twice, first time is to force display, 2nd to hide). Then whenever there was a quest turn in in a zone I was doing a MSQ in, I'd just go there. Makes it a bit less annoying like this.