Q.Two questions…
1) I’ve been harvesting my Mr Stripey and Big Boy tomatoes, and they taste a bit salty. What would cause them to have such a salty taste?
2) I went on vacation for a week, and left very specific instructions on how to care for my garden while I was gone. Even though my instructions were followed, my container garden seems like it’s almost dead, while my ground garden is in great shape. I know that my region was hit with a lot of rain while I was gone, but it didn’t seem to affect the ground garden. What can I do to save the plants that are struggling to survive in the container garden?

This is not an uncommon complaint among growers of hybrid plants.
Genetic mutations can be the cause of tasteless tomatoes or tones of flavors that are not appealing.
This is one of the many reasons in the popularity of Heirlooms.
Seek out some varieties you may enjoy for next years gardening.
Little can be done for container plantings that suffered from neglect. Remove dead material trim back to green material.
Continue to care for them with proper watering. A boost of nutrition with some Epsom Salt may help.
Here are some links for you.
https://www.gardeningknowhow.com/edible/vegetables/tomato/heirloom-tomato-varieties.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/epsom-salt-gardening.htm