Hi there - check out RNAlater or RNAprotect (Invitrogen, Qiagen) https://www.qiagen.com/us/shop/pcr/rnaprotect-tissue-reagent/ and https://www.fishersci.com/shop/products/ambion-rna-i-later-i-stabilization-solution-7/AM7021
or RNA Shield from Zymo (https://www.zymoresearch.com/collections/dna-rna-shield)
These should stabilize RNA at room temperature, though additional cooling/freezing can be beneficial too.
I hope this helps you. I am trying to find the best option for my samples too!