Stick to your numbers and strategy but be flexible on the exit. 

Lenders might be more flexible if they know it’s a short-term loan, especially if you plan to sell the property quickly.Have you considered working with hard money lenders or other asset-based financing?

Equity in the DealOffering equity instead of—or in addition to—interest is another popular structure, especially if you need flexibility on cash flow.

If you have the flexibility to do it, I'd absolutely go for it!

I am seeking advice on finding equity investors or lenders who can offer more flexible payment schemes with low or no downpayment at the beginneing, particularly for construction projects with a timeline of approximately two years.

We’ve found doing value add to be a way to force appreciation and add cash flow when we got our house… we added an ADU and house hack with a midterm rental to generate the additional income and make a bigger home actually affordable but still flexible for when family visit 

However, we do have the flexibility to rent it out.Our goal is to refinance the property, as we initially purchased it with an interest-only mortgage, and get it rent-ready.

This can kill a a project if you don't have flexible financing.Also, try to have multiple exit strategies.

@Casey Johnson You can leverage your personal residence to fund your BRRRR strategy by using a HELOC once your home is far enough along, giving you flexible access to your home’s equity.

Banks and credit unions can also offer flexibility for investors that engage in strong relationship-building strategies, offering discounts and solid loans in exchange for borrowers willing to use the institution for other purposes (savings accounts, etc.).