A couple of news media sources actually did some investigative reporting and came out with reports about who's been funding all the agencies that are promoting the Big Lie, including Turning Point USA, Project Veritas and the Heritage Foundation. From The Intercept:

Among the corporate donors to Bradley Impact, according to the tax document, were ABC Supply Co., whose website describes it as “the largest wholesale distributor of roofing in the United States”; the Boelter Companies, described online as “a provider of supplies, equipment, and design solutions for commercial foodservice, hospitality, and beverage industries”; and Bandon Golf Courses, which operates a number of golf courses in Oregon. Other donors include a former music industry CEO in Wisconsin, the CEO of a company that provides equipment to pipeline companies, and a number of small family foundations. (Neither Bradley Impact nor the donors listed in the tax filing responded to requests for comment from The Intercept.)

The largest donor to Bradley Impact listed in the fiscal year 2018 filing was the Milwaukee-based Lynde and Harry Bradley Foundation. A much larger, linked nonprofit, the Bradley Foundation was identified by a recent New Yorker article as “an extraordinary force in persuading mainstream Republicans to support radical challenges to election rules.” The report described the foundation as a key promoter of the idea that election outcomes unfavorable to Trump are the result of fraud, doling out millions in grants to projects in the United States aimed at disqualifying purportedly illegitimate voters from participating in elections, according to the New Yorker, while using the issue of election integrity as a way of both undermining faith in the democratic process and manipulating election outcomes in a manner more favorable to candidates aligned with Trumpism. According to the 2018 filing, the Bradley Foundation gave $2.5 million to the Bradley Impact Fund.

The Bradley Foundation said in a statement that the Bradley Impact Fund is a separate group. Five of Bradley Impact’s board members and officers hold board seats at the Bradley Foundation, and the Bradley Impact group says its donors’ outlook is aligned with the larger foundation.

It should be noted that the owner and CEO of ABC Supply, which is located in Janesville, Wisconsin is Diane Hendricks, who inherited it from her late husband. Hendricks first came to the state's attention when a video of her meeting with Scott Walker, urging him to introduce Right to Work and other malevolent policies. Walker then revealed his "divide and conquer" plan to attack all the unions.

Hendricks contributed millions of her own dollars to pro-Trump groups as well as to the Orange Shitgibbon himself. These donations were just a drop in the bucket for the multibillionaire. So it should come as no surprise that Trump appointed her as an economic adviser in 2016.

It should also come as no surprise that she and others of her ilk would be promoting the Big Lie.