Can I get a TN visa a year before my current expires?

My current TN visa is valid for 4 years (I'm mexican). My I-94 expires December 31st this year and I saw that the cost of extending it an extra year is quite high. So I was wondering if it would be a better option to just get a new visa 1 year before my current one expires and if that's even possible. I'm a Mexican citizen, my current visa has been my second TN. First TN was valid for 1 year, current one is valid for 4 years. I mainly want to avoid having to pay for extension and just a year later pay for the new TN. Looking for recommendations of people that have been on the same situation. In case that I have to extend my I-94 will that prevent me from leaving the country due to it potentially overwriting my allowed extension date?