Why do you need to toss shampoo bottles every night? Is there something preventing you from using a slightly larger travel bottle(s) for multiple uses and refilling when needed? Or even buying half a dozen empty travel bottles and filling them all at once as a mini toiletry supply to "shop" before each trip? Genuinely confused.
Matador sells a soap bag made of breathable technical fabric so you can put in a wet soap/shampoo bar and it should dry
https://matadorup.com/products/flatp...12135840874609 Some people just wrap the slightly damp bar in a bit of scrap fabric so it doesn't get stuck in the soap container. You can also cut shampoo bars into pieces if you're going to toss wet bits but honestly a quarter of a Lush bar is still more than hip length hair could use in a single shower.
ebay has bulk lots of travel shampoo bottles for hotel supply
https://www.ebay.com/itm/140-Bulk-Lo...cAAOSwgFldyTup
https://www.ebay.com/itm/Lot-of-Neut...xTiZOhSQwT7Zzw
I like the oval standing shape for Pantene (Radisson) or Neutrogena (HGI, Hampton, etc) and actually refill them via pump bottle of shampoo or small funnel.