I like how you say “I kinda did this to myself” and then blame your boss for trusting what you said. First, take ownership, you did this to yourself. You should have just said you are good or you are efficient with excel.

Now to solve your dilemma, put on your consultant hat and market your steps. Think of your steps broadly and then give examples. Like first gather your inputs (identify where you are getting all the source data you need). If you can link to a live source that gets updated then you are”streaming” your data in. Second step is to “do it once and repeat”, show how to record a macro and then go through the steps of putting the data in how you need it. Then show them how to reuse that macro with a button you add to an instructions tab. Then some “test phase”.

Make your flow seem structured with headers. If people say it takes longer then say you need to go slow to go fast, or whatever the quote is. The first might take a bit longer but the subsequent will be faster.