Ethercalc is good tool which can be selfhosted. It is fairly simple to do so. Though it will be available for anyone who has the URL because there is no inbuilt login mechanism.
I did not dig into making it accessible with a login interface as I lost interest after I made it work on my server and played around a bit with it but it was simply because I got interested in other things and not because the tool isn't fascinating enough. I am fairly certain this will not be overly complicated but for a simple selfhosted spreadsheet solution this is definitely worth playing around with.
#Ethercalc plays well wth redis as per their documentation. So Install and start 'redis'sudodnfinstallredis
sudosystemctlstartredis.service
#Test if 'redis' is workingredis-cliping
#Enable redis to automatically start at the time of system start-upsudosystemctlenableredis.service
#check if it runsethercalc
#Press Ctrl+C to exit#To run it forever use pm2pm2startethercalc
npmlist-g--depth=0#Change port to whichever port you want Ethercalc to run on by opening app.js #and changing port.nano/home/<yourusername>/.npm-global/lib/node_modules/ethercalc/app.js
#change port and save#run with pm2 and alias as Ecalcpm2startethercalc--name'Ecalc'#check logs using pm2pm2logsEcalc
#Reverse proxy Ethercalc using nginxsudonano/etc/nginx/conf.d/ecalc.conf
sudosystemctlrestartnginx.service