Frankly, the answers you received show no understanding of your problem. They are fine for consumer debt, but your issue is business debt.
I don't know where you are that a 15% interest rate is reasonable for this situation...but let's assume it is.
You have a few possible solutions:
First, find a partner who believes in you and your business and can invest through equity rather than debt. This will reduce your monthly costs
Secondly, approach your lender(s) to renegotiate a longer term loan with lower payments. I don't know what your security was against the loans, but if it was the business assets the lenders would prefer repayment rather than taking over your business and maybe getting pennies on their debt.
Reduce the loans through assets sales, as you have suggested.
Whatever path you take, get a good advisor to work with you, as you might be blinded by bring in the business. They can bring an outsider's eye to your problem.
Good luck in your future!

Ah...yes. They should be thinking in those terms well before product launch. A formal SWAT analysis is simply a tool to help you think about those 4 important areas.
Strengths - what is it about you that makes you superior to other potential competitors
Weakness - what are your internal flaws that threaten your success
Opportunities - who are the most likely customers/markets for you, and why
Threats - who could eat your lunch, derail your product and steal your customers.
Here's a good visual representation that can help:
https://images.app.goo.gl/NpBvVvxiisVG6C3Q9

Having been working with and advising companies on how to get great customer feedback for many years, I have a couple of ideas you could try.
One of the key assets you have is your customer list. You already have permission to approach them, I assume, so reach out to some to start a dialogue.
If you are able to segment them by sales, you can approach your great, repeat, customers with a simple question such as "What is it that you and your dog like most about our brand?" and "Are there items you are looking for that you haven't seen in my shop? If so, what?" or "What were you looking for the first time you found us?" Don't blast them to everyone, don't "survey" them, just ask the occasional probing question to try and understand what the "job" was they were looking to do when they engaged with you.
Another possible idea is a have a monthly contest where you ask a question in your newsletter and enter anyone answering into a draw for a small prize. Then publicize some of the best answers and give a shout-out to the winner in the next newsletter.
At the end of the day, you want to simply start a conversation with your customers, so you can listen and react to what they have to say.
There's only so much to cover in this forum, so please let me know if you have any questions.
Steve

Having worked in this area, both as a client and as a consultant, customer understanding is a key to differentiating yourself from your competition.
First a personal belief: surveys are the worst tool to uncover any insights. They are best used to quantify how many do X.
There are a couple of ways we look for insights into customer behavior, and they are both related by fact that you learn by observation.
First is to have your customer demonstrate how they use your product/service, or the product you want to replace, in their normal situation. Ideally you let them run through once just observing what they are doing while taking notes. Then ask them to go through it again where you ask them open-ended questions as they go along. No judgement, just watch and learn.
The second way is to engage them in a serious game, something like the ones we use from Conteneo.co. These are frameworks designed to have the customer create things like the Product Box which encapsulates the key features, benefits, etc. that they are looking for in an ideal product/service like your.
The reason these techniques work well is that the customer is comfortable, they are not being interrogated, and you are cast in the role of the observer, so you're not selling!
Let us know if there's something we can do to help you with this, because it's an important question.

I've spent more than 20 years helping people understand their customer's needs, and it starts with listening and observing.

First, you either need to invest time or money...there is no other way. I would suggest time, and I would refer you to the Lean Startup methodology. I good online resource is leanstack.com, Ash Maurya's site.

If you have an idea you think might solve a problem for someone the first step is to validate that who you think has the problem actually does have the problem, and they have tried to solve it, have spent money trying to solve it, but still have the problem.

So identify potential customers and go talk to them about the area you are interested in. Don't pitch them a solution yet until you have validated the above hypothesis. Listen to what they say, watch what they do.

This is a starting point, so check out Lean Startup or Business Model Canvas.

If you want any additional details, give me a call

In my experience advising start-ups, you can never get enough hand's on time with customers, or potential customers. As Steve Blank says, get out of the building. Too many time opportunities are missed because the founder waited until he/she felt everything was "perfect". Your level of perfection can only be truly judged by the customer.
One of the advantages of doing beta testing is that your users will understand that the product/app may not be flawless and certainly will not contain every feature that they would ultimately want. So put it out there and engage your users in meaningful conversations about their experience. Listen hard to try and understand two main things: if the user doesn't like something, why? If they do, why? It's just as important to understand the reasons for your success as it is your failures, because at the end of the day, you win or you learn.
Good luck, and feel free to contact me as you learn. I may not know your domain, but I know about listening to customers.