I'm self publishing a book but it's a small ebook I am in the process of looking for an editor for it but I don't want to self publish a big fantasy book right now just a standalone book based on what I'm able to write I guess you can say quality not quantity but is that the case with fantasy books? It's not something I was aiming to make a web novel so don't ask me to upload here
Novellas are quite popular on Amazon, I believe they even have a category called quick reads or something of the like for it. So I don't see why you wouldn't find an audience there as long as you market your book.
The first arc is quite fast paced will that kill readership? If so should I rewrite it?
That is a very subjective question, but if you want to get feedback on your manuscript, you can start a new topic specifically asking for people's thoughts on the pacing.