The value of whatever stock you hold is likely to become severely diluted upon an acquisition. So unless you are holding like 20%+ of stock it might not be worth that much down the track. If I were in your situation I would get an expert assessment of how much your stock might be worth down the track, i.e. like best case and worst case. Then you will know whether that is enough money for you to grit your teeth and hang in there.

I presume from details that the company is profitable and will continue to be so.

BTW are the founders assholes to the customers as well? If so, then there could be cancellations coming along. If customers are by subscription or some annual renewable basis then you will need to monitor the new customers vs the lost customers ratio. It is not unusual for companies to do well initially and then start bleeding customers when poor support and aggressive tactics come into play.