I use this shell script whenever Magento 2 is behaving strangely. It takes a long time to execute (mainly due to deploying static content), but it's a good last resort which usually solve my problem.

Refresh Magento 2 Commands

#!/bin/sh
  
RED='\033[0;31m'
NC='\033[0m'


echo "${RED}Deleting pub/static ${NC}"
rm -r pub/static/*

echo "${RED}Deleting var/cache ${NC}"
rm -r var/cache/

echo "${RED}Deleting var/composer_home ${NC}"
rm -r var/composer_home/

echo "${RED}Deleting var/generation ${NC}"
rm -r var/generation/

echo "${RED}Deleting var/page_cache ${NC}"
rm -r var/page_cache/

echo "${RED}Deleting var/view_preprocessed ${NC}"
rm -r var/view_preprocessed/

echo "${RED}Upgrading... ${NC}"
bin/magento setup:upgrade

echo "${RED}Compiling... ${NC}"
bin/magento setup:di:compile

echo "${RED}Deploying... ${NC}"
bin/magento setup:static-content:deploy -f

echo "${RED}chowing...${NC}"
sudo chown -R $USER:www-data .