If anyone is using kodi on their firestick stick with 19.3 or 19.4 and use minimal stuff, like the crew, seren or @Jayhawks659 skeleton crew Here with real debrid.
20 is a big update and has alot of stuff added which is using more ram, space and resources to function. By adding addons or builds means its working harder so there will be crashing and low memory while using this version on your firestick. Id use it on a stronger device with more ram and storage. I see alot of topics and comments of 20 so for now stick with older version on your stick or use kodi on a better device. (Cube/shield/forumler/pc)