I use this type of thing:

https://www.cromwell.co.uk/EAR9586610V

Easy to fit into your lughole, washable and cheap.

I generally keep the cord and tie round my neck when the helmet comes off, so they rarely get lost. You may find them more comfortable if you trim the plug so less sticks out of your ear.

Personal choice I know regarding comfort & fit- anything to avoid risk of tinnitus.

Good luck with your aural quest.