@LowQualityRepublic pin gems comment. It's literally the solution.

• Check wing connection
• Play around with weights
• Check stabilizer placement and size
• Check landing gear placement and traction
• Check part placement for whatever's off too right and which is heaviest
• Check part connections and see which part has way too many connections that make it's weight lean to the direction it's veering towards

i will pin the working solution so try thinking about something smart.