Watch Battery will not last

No you cannot, it is not user replaceable and TT does not offer this service. You can try cracking open the case (voiding the waterproofing and warranty) and replacing it yourself, but I would not recommend it. I would first try a factory reset and then a roll back to the prior firmware at the link below (the latest update causes battery drain issues.

https://en.discussions.tomtom.com/spark-and-spark-3-runner-2-and-runner-3-473/unable-to-pair-sync-after-update-to-firmware-v1-7-53-runner-and-spark-watch-series-1030088

I hope this helps answer your question. If so, please mark it as a solution so others can look for it if they have the same question.