Two suggestions:
1) It sounds like at least one of your dogs loves balls and squeeks, like mine. I just bought this: https://www.amazon.com/gp/product/B00KNWVPFO/ref=oh_aui_detailpage_o04_s02?ie=UTF8&psc=1. Its rubber so won't pick up the dirt and grime that can wear down teeth, but is pretty tough so far. The dog pops soccer balls like its her job, but this has held up. The squeaker has survived pretty rough play, despite what some of the amazon reviews said, so that was a happy surprise. Its also just a different type of play versus fetch with a tennis ball, so I think its been a fun break for her.
2) Kong frisbee. Soft, but strong kong rubber frisbee. It has some reinforcement around the rim so it can double as a tug toy. My dog hated frisbees before this thing. She does love tug, so giving her a little action of that after fetching it got her going. Maybe that is a way to transition off of the fabric ones?
I like seeing these sunny updates! It's like my pup in red.
For beach-going, if he likes fetch, I love this Kong Jumbler ball. It floats with the handle up so they don't have to get water in their mouth to grab it. I did get a little water in mine yesterday, so waiting to see if it dries out ok.
A friend of mine has a massive GSP and he LOVES this ball, when I was there I could tell how durable it was.
My pup Dobby has had his since Christmas and it definitely has battle wounds but he hasn't been able to murder it. It's his favorite toy to play fetch with as well.
KONG - Jumbler Ball - Interactive Fetch Dog Toy with Tennis Ball (Assorted Colors) https://www.amazon.com/dp/B00KNWVPFO/ref=cm_sw_r_apan_i_YQY088095YG88T3GW14G
Our Aussie Cayde live to chew and chomp, so we found this
KONG - Jumbler Ball - Interactive Fetch Dog Toy with Tennis Ball (Assorted Colors) https://www.amazon.com/dp/B00KNWVPFO/ref=cm_sw_r_cp_api_glt_i_40H6E98NJPRBNZ9Y7CJA
He Loves this thing and even with his non-stop chewing it makes it a year, and then he gets the tennis ball that is inside as a bonus
I linked to the wrong toy on my post. This is the correct one. A month now and still going strong. Not only has the toy survived a dog who destroys EVERYTHING in seconds, but he's still absolutely fascinated with it. Totally worth what I paid, and if he does kill it now, I'd buy another immediately.
Made by "Kong" (bought in UK)
https://www.amazon.com.au/KONG-Jumbler-Interactive-Assorted-Colours/dp/B00KNWVPFO
Kong Jumbler, has tennis ball inside and handles to grip. My dog saw it at the dog park so we got one. Had it for 6 months so far.
KONG - Jumbler Ball - Interactive Fetch Dog Toy with Tennis Ball (Assorted Colors) https://www.amazon.com/dp/B00KNWVPFO/ref=cm_sw_r_cp_api_glt_i_8KK48MR4A7BV3E9BAZKB