Brake Light On problems of the 2008 Toyota Sienna

About a five years ago the slip indicator light (car with swervy lines) started coming on intermittently while turning on highways etc. (but not when any risk of tires slipping). I brought it to Toyota three different times over the years and Toyota always states they can not duplicate issue and states they can't fix it but maybe drive slower (really it has nothing to with my spee after years of dealing with this its been something we just deal with). The vsc light also comes on and alarm sometimes sounds while driving. Two more trips to Toyota and several visits to different mechanics and nobody can find out the problem. In the last 6 months the abs system is also being activated without me applying the brakes. It does it without warning. All of these issues can be on a curve at different speeds or on a slight or medium turns (not real sharp turns), going uphill or downhill and left or right. Our van has about 150,000 miles on it now on 2020 but when the problem first started it only had around 110,000 miles on it. We have changed brakes, tires, rotors, brushing on advice from different mechanics to try to fix the issue. Nothing works. Toyota cannot figure it out. It's becoming more dangerous because now the abs is being activated with this problem. I can't tell if my brake lights come on so that drivers behind me can tell that I'm slowing down very quickly. This jerks those in the car and I'm afraid we may lose control. I have read on different web sites that this is common with a Toyota and it's just not my van. If I had the money I would buy a different vehicle but being on a fixed income I don't have the luxury to do so. How can a car company have so many complaints from consumers about this common problem but still can't tell us how to fix it? it's Toyota's design they should be able to tell the consumer what is causing this issue and how to fix it.