My advice (for what it's worth) is to use the MSQ skip if you are going to use a skip potion. I will back this up for four reasons:

1) The main scenario missions are comprised primarily of painfully tedious and pointless fetch quests and there are HUNDREDS of them. I'm not exaggerating either. If you are still in 2.0 story, you have a mountain of questing to do that will take a significant amount of time to complete, even if you go fast.

2) Skipping MSQ will unlock dungeons and trials up to 5.0 which can be used to level and gear your character fast if you main a tank or healer. Subsequent classes behind your main also get the armory bonus for 100% extra xp until level 70 and 50% to level 80. The armory bonus also stacks with food and FC buffs.

3) Information and cutscenes you miss in game can be accessed via other methods. There are YouTubers out there who focus specifically on the lore and story of FFVIV. I don't know if he is still making videos but Ethys Asher has some really good ones.

4) Grinding out the main story up to 5.0 will almost certainly burn you out and you will probably quit the game again.

You can level a class to 80 in a fraction of the time it will take you to catch up to the current story. It may not be the most popular opinion, but if you want to enjoy the game, and you're that far behind, I would use the story skip.