Recommendations for summer (June/July?)

We have been to Japan 10+ times, and it was always Tokyo, Kansai, or Hokkaido. Would like to try something new next time around. What do people recommend, specifically around the summer? Is there a destination that has a little bit of everything, food, sightseeing, beach, etc.? Thanks in advance.

Tohoku.

It's not as cool as Hokkaido, but definitely cools off more at night than Kansai. It also has a lot of areas that are either really cold or closed for some of the year. Some places are hard to reach without a rental car.

I really liked Osorezan (rental car)
Towadako (you can get there by bus)
Dewa Sanzan (Yes, I know the pagoda is being worked on, but if you are not always there in Summer, July is one of the few times you can visit Gassan and Yudono-san also has a limited season.)
The hydrangea forest near Ichinoseki (best by car)
So many onsen
Lots of hiking and nature and honestly just go through Japan Guide. I haven't been to so many places and there are so many I would like to visit.

You did not mention that you have been to Kyushu, so maybe there. A trip to Yakushima Island, maybe going to Miyazaki for a few days, up to Takachiho, and then to Beppu.

You said you have gone to the Kansai region, but have you gone to the Kumano Region South of Osaka. There is an interesting Fire Festival in the middle of July.

https://diversity-finder.net/tourism/nachi-no-ogi-matsuri-wakayama

There is also Takayama, Shirakawa-go, Kanazawa, and the Alpine Route to explore.

And… Since you may go in early July, you might consider going to Tanabata somewhere. There is a place near Tokyo that celebrates on 7/7, Hiratsuka.

https://www.japan.travel/en/articles-from-2020/shonan-hiratsuka-tanaba...

Good Luck, in planning your trip!
Maybe these will help.

It may not have beaches - but the word "Tohoku" is coming to mind at the moment.

This is also a great driving destination as well - as there is lots to do but it's a bit more spaced out than other locations in Japan (apart from Hokkaido).

And because it's on Honshu - it actually has a long history compared to Hokkaido (which is a historical wasteland if you remove the Ainu culture compared to the rest of the country).