Funding advice for $8.5m EBITDA software deal

I've been discussing directly with the founder to acquire his $8.5m EBITDA consumer software company in a proprietary deal. I come from an operator background, having exited my company to a Fortune 500 in 2016 and remained as a Director for the F500 for 7 years. I only have M&A experience on the buy-side and operator experience vs fundraising experience.

This acquisition could approach $100m and can support a lot of leverage given its strong profitability. I plan to personally invest around 10-20% of the equity and look to raise the remainder. What advice do you have to fund a deal of this size? I'd like to approach this as an IS/SF and partner with another IS/SF with a proven deal history and strong capital connections (preferably family office and debt providers). With my strong operator background and desire to run the company post-acquisition, partnering with the right IS/SF whose strength is on the capital side, might be a great fit.

I appreciate any and all advice.