2021 Tundra 1794 Wheels and Tires

Hello Everyone,

I have a 2021 Tundra 1794 Edition. I am looking to put some new wheels but am not sure about sizing. I want to keep the wheels at 20". The truck is stock height.. What i don't understand is the offsets and wheel width. I found that the wheel is 20×8". If I wanted to use the tires I have now, 275/55/R20, what wheel sizes are my options. For sure the wheel has to be 20" diameter, but does the width also need to be 8". What about the offset. The wheels now are said to be 60mm. What do offsets mean and do the new wheels have to be 60mm as well. And if u decided to get other tires, what size would you recommend. What will fit without any additional modifications to the truck

Thanks in advance