Personally I would suggest a Lowrance GPS for any type of racing.
I use it for Off-road Racing and love all the features about it.. primarily to mark a course.
If it wasn’t for racing I have no need for it and or a reason to spend the money on a pricey GPS.
My iPhone/iPad google maps gets the job done, but there is a good app I like: onX Offroad
I believe its free for like a week or two then you pay after for all the bells & whistles.
I use it as a back up and you can also mark course. Check it out