If you are able to purchase your hot tub with a credit card you should check out the extended warranty provisions of the card you use. Of course, you should only pay by card if you can pay off the balance and avoid the crazy high interest rates but if you can do so, some cards provide extended warranty.
Pre-Covid I travelled extensively and I usually select the card to use when buying things based on point value for travel but when purchasing expensive items or electronics I prioritze extended warranty provisions. My go to card is usually the Citi Costco card which adds two years in addition to the manufacturer's warranty, up to a total of seven years. That is, a five year warranty would be extended to seven years. This can be esecially helpful for lower priced tubs with shorter warranty periods. I haven't seen a card with better extended warranty but if you know if one, let me know.
I have no association with Costco or Citi...