You don’t need to share with a lawyer any posible profit from suing , you can pay an Intellectual property insurance and it will cover the process (depending on the total insured)
Note: it will protect you over future infringements (not those happening right now, I think none yet, correct ?)
There are affordable offers in the market
I hesitate to suggest it, but you could look into Intellectual Ventures. According to Wikipedia:
Intellectual Ventures is an American private equity company that
centers on the development and licensing of intellectual property.
Intellectual Ventures is one of the top-five owners of U.S. patents,
as of 2011. Its business model focuses on buying patents and