I have been a long time Mazda
I have been a long time Mazda Owner for almost 20 years.... currently own a 2020 Mazda3 AWD, a 2020 Mazda Cx5 and a 2021 CX30 for my family to use...in 20 Years I have never had one issue with the 12+ Mazdas I have owned.... Nor have I heard any issues from other Mazda Owners I have met in my dealerships Service Dept...I sounds to me like you have some enemies out there who are sabotaging your cars... PS> Consume Reports just rated Mazda#1 for reliability for 2020 and they have been in the top 3 in Reliability Standards with Consumer Reports for the last few years... so it clearly sounds like your issues with Mazda are isolated to you and how you take care of your cars