Tour recommendations for Capril and Amalfi/Positano - staying in Sorrento

Do the Blue Grotto. Also, you want to see Capri Island, Emperor Tiberius lived there the last years of his life and I think there are ruins of his palace.
Take a tour of the Amalfi Coast, usually it is a bus tour, prefer the smaller busses.

You don't need a tour of Sorrento, do it on your own.
https://www.tripadvisor.com/Attraction_Products-g187780-zfg11873-a_contentId.1188572355524159+268395744-Amalfi_Amalfi_Coast_Province_of_Salerno_Campania.html
https://junipertours.com/destinations/italy/amalfi-coast-tour-with-capri/

We were also based in Sorrento and we did a tour of Capri with Mondo Guides.

https://mondoguide.it/city-tours-from-sorrento/capri-classic

We discovered this tour company because Rick Steves had mentioned them in his book- that they had a special tour for Rick Steves guests. After some research, we liked what was offered in their general capri tour and booked that.
The tour included a ride on the ferry over to Capri from Sorrento, a private minibus to Anacapri, a chance to ride the chairlift up to the highest point. We opted to visit a villa. Then a visit to Capri, then a boat ride around the island, where it stops at the Blue Grotto for an opportunity to visit that. I say opportunity because when we went the Blue Grotto was closed due to high tide, but we didn't care because the boat ride around the island was spectacular and much better than the blue grotto. Then a ferry ride back to Sorrento. it was an all day affair.

This tour company also has tours to the Amalfi Coast.

Thank you. Is it better to go by boat or bus from Sorrento to Positano? I have read that the traffic is horrible, so I wondered if boat would be better?

For sure the boat. The bus can be quite horrible if you get car sick, and it can be crowded as well. People were running to get a place on the bus in Amalfi when I was there, and it has gotten much more popular in the years since.
On a positive note, late May is a great time to be there (usually)!
I would go to Positano one day and Amalfi another day, time permitting, While in Amalfi, you can go up to Ravello by bus if you desire.

I have booked 2 boat trips from positano.com. One goes from Sorrento to Positano and Amalfi with a few hours shore time at each town. 47 euro pp. It's not a guided tour but the views from the water are amazing (I did the same trip a couple of years ago). I have also booked through the same company, a similar excursion from Sorrento to Capri. It includes a trip around the island and several hours free to explore Capri. It was about 75 euro pp, including transportation from the hotel. It's a big website with hundreds of possible excursions but I think it's well worthwhile looking through it!

I saw some really negative comments about HP travel (Positano.com). Your trip was fine?

yes, it was fine. it was a few years ago. there are some negative reviews about everything. it's hard to please everybody I guess.