Fun facts

1. Summoner has ONLY 2 abilities during Ifrit phase that needs long cast time and 1 of these can be insta casted with swiftcast that is a general ability for all caster mages. (put it on your cast bar) Summoner is one of the best mage in some ultimate runs because it is basically a non-caster caster... so I think if you find this one difficult to play, the problem is perhaps with your knowledge of the class.

2. There is an option in the game under character settings where u can set visualisation of your, your team members and other spell effects. GO to your settings and set them "show limited" or "show none" if you don't want to see them. Party spells are good to set to "show limited" so you can see shields set on the ground.

3. If you feel that there is an issue with someone in the party, cause they are rushing, perhaps you should type in chat that "hey, im new, please go slow cause I would like to enjoy the run"
It happens to me sometimes in dungeons where there are "readable" content. If I go as a tank, I will wait for them to read the things.

4. there may be other players with you who are sprouts and have no clue what to do, so you yourself should be more patient with tanks when they have the sprout icon on their name.

FFXIV does have many issues but none what you noted are unsolvable.

Please have a bit more open mindset and feel free to ask people for help if you feel you struggle with something, because the issue might be not with anyone else, or the game, but within you...

You may also use the "trust" system where bots are overprotective about the player.

In any case, I cannot change your mind. These are just pointers to think about. At the end you can decide what you want to do.