You are not going to find a template that’s very effective for each and every BR you come across. The key is to create a unique, customized BR offer message for every BR. You need to customize your message according to the buyer and their needs (and not just change the message that goes inside the brackets that say “buyer’s needs”).
That’s a great first step. However, you should also point out the way in which you will go about meeting the buyer’s needs/demands or achieving the project’s goals. This is where your next point (skills) comes into the picture. When you talk about the approach you will take to achieve the project’s goals, you should also elaborate a little on how your skills/prior experience will help you achieve the project’s goals.
It’s not a deal-breaker, tbh.
I see that you offer video editing. So what you could do is take a raw video of something you are interested in (or a video in which you can effectively display your skills) and then convert this raw video to a professionally edited video. You can then upload this as a sample to your gig. Your buyer is mainly interested in getting a feel for your skills, expertise, and style. And doing the above-mentioned will do just that.
Also, if you are interested, you could have a look at this forum post on how to write a good BR offer: