Which dialect do i go for?

Hello. I am showing intrest in learning spanish, and plan to use online teacher. There are lots of options on preply. Most of the spanish that i will use is prob for school and a trip to mexico. Should i hire a mexican teacher then? Or a spaniard?

Im asking this due to dialect differences. I heard that chilean and argentinian i should stay clear of as they are very different compared to other spanish dialects?

Which countries teacher do you think will suit me best? I assume i will be learning dialect based on teacher...