I think you have a good idea and the story progression is good but you might want to work on your power scaling and fleshing out of relationships The MC has a good amount of powers to learn and draw inspiration from with the sand fruit but you are limiting him quite frequently and it becomes frustrating watching the MC limit himself to one ability against weak antagonists. Additionally though his current weakness does make sense as he hasn't trained for very long, he still should be far more effective and creative with his powers taking down fodder ,like the gravity villain, nearly immediately. MHA can be irritating to power scale as most strong villains don't appear till later in the story but if the MC is in a fight with an original villain try give more credible reasons as to why he would struggle like he does instead of having the MC take frustratingly long to stop one group of cannon fodder. Making the MC too strong can be a credible fear for the story but it can be used to add some character growth as the MC could become arrogant fighting fodder for so long, only to be beaten by a cannon villain like Shigaraki when they fail to take his threat seriously and they (or someone else) gets hurt by the MC's arrogance. I also feel like your relationships between characters could do with some work. This is usually very difficult for a fast paced story like yours, so I would advise either remove some time skips and slow the pacing or thoroughly plan interactions between characters. I think it would also be more organic if the MC had more interactions between his parents or friends just as slice of life as it would give the MC more depth and avoid you as a author falling into the troupe of having a cool and strong MC with no depth or actual character to him. all in all I think your story has great potential and could be really good just work on the interactions and his use of Haki and it would be even better.
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