https://techcrunch.com/2021/01/12/2021-a-spac-odyssey/

There are a number of ways to take a private company public: You can pursue a traditional IPO, sell a chunk of shares at a set price and start trading. You can direct list, and merely start to trade. You can host a hybrid auction-offering, like what Unity did.

Hell, Google showed us back in the day that a reverse-Dutch auction is possible, after which no one else deigned to try it.