We received 25k investment offer, need advice [I will not promote]

We received a $25k for 2.5% on a convertible note offer from a US based investor. The note matures in 18 months with an interest rate of 5%, but the investor said they can extend it further.

It’s an AI SaaS in graphic design. We have been bootstrapping till now, and we feel that this money could help us hire better engineers and marketeers, we want to grow it to a good revenue, but don't see it becoming a billion dollar startup as such. Our initial plans were to build it like an indie-hacker, grow it a decent revenue and sell it to someone who can take better care of it. We built it as a side project with full time jobs.

We already have decent traction with 10k+ signups and $600+ in revenue per month with <100 dollars spent on marketing. But our AI model costs are high, 0.2 USD per user that we onboard and provide free credits.

But we as founders are more interested in another idea that we have been thinking about and see a bigger potential + founder market fit in. The current product is good, and we can foresee that with better hiring and marketing, we can grow our revenue to about 10-20k a month, like a regular online business. What should we do?

We don't want to simply let go of the product because it's not that it doesn't work, it's just that we as founders are better fit for something else. We can't sell it yet as the revenue isn't too high and we haven't even incorporated. Is it okay if we think of growing it to 10-20k+ a month and then intend to sell it to someone who can take better care of it? Should we take the investment in such a case, given this investment is definitely gonna help us grow? Process of incorporation will also help us in selling this business later I think?