The BCCI may be able to find another sponsor
The BCCI can easily find a sponsor, IPL is not a small domestic tournament, it is an international tournament that has a fanbase and viewship across the globe.
I don't think that it is possible for the BCCI to unilaterally cancel this deal, unless they reach a compromise with Vivo. Also, other sponsors may not be willing to pay this much for the IPL sponsorship.
The deal can easily be cancelled! but, Why should BCCI cancel it? when BCCI is bringing in Chinese money to India and not sending Indian money to China.
Those who are opposing this deal are basically contradicting the narrative.