I finally did it and bought a Sony a7iii after saving up forever and i am so hyped to start taking actual photos but honestly i am totally lost. i have been watching youtube videos for three days straight and my brain is basically mush at this point because there are just so many options for lenses and i dont understand half of the terminology people are using. like what is the difference between a prime and a zoom and why are some of them so heavy?

I am heading out on a dream trip to Japan in about three weeks and i really want to capture everything from the neon lights in Shinjuku to the quiet temples in Kyoto but i really dont want to be that person carrying a giant bag of gear and swapping things out every five minutes. i just want one lens that can stay on the camera the whole time and handle everything i throw at it. my budget is right around $800 to maybe $1000 if it is really worth it but i would prefer to stay on the lower end if possible since i still need to buy sd cards and a extra battery.

I saw some stuff about a Tamron 28-75 and a Sigma 24-70 but then someone else told me I need a 35mm or a 50mm if i want that really blurry background look for portraits of my wife. is there one lens that can kinda do both things? i am looking for:

• something that isnt too heavy to carry all day
• can take good photos in low light like at night markets
• has a good zoom range so i dont have to walk everywhere
• makes the background look professional and blurry

I am so sorry if this is a dumb question i am just a total beginner and the more i read the more confused i get about what is actually the best all-around lens for someone who only wants to own one piece of glass for now...