I posted this elsewhere, but this site offers a (non-scientific) but very useful sound guide for each of the ear plugs reviewed, volume normalised. I found this very useful as I was able to pick up some cheap generic plugs that offered better speech intelligibility versus some that I have that seem to be more bass heavy. I have another set here that are really peaky around 2Khz, which is really fatiguing, so making sure I didn;t end up with another simialr set mean this site was invaluable.
I have to say, these would be only short term use as all generics hurt my ears afetr a while and rarely sound as good as a set of moulded Pro plugs. Mine are 64 Audio, but I do have a set of the "Help For Musician's" moulded plugs by ACS through the Musician's Union too - highly recommended for busy professional bassists.
https://www.hearadvisor.com/earplug-rankings
https://www.helpmusicians.org.uk/get-support/physical-health/protect-your-hearing