Sudden turn off when not connected to power and WiFi disconnect

The iPad turns off suddenly when disconnected from power even when has 100% indicated.

additionally the iPad sometimes shows the WiFi signal in grey, so that it’s impossible to press.

is it just an old battery issue or something else?

tia

crwdns2934089:0crwdne2934089:0 crwdns2934093:0crwdne2934093:0

crwdns2934109:0crwdne2934109:0

crwdns2889612:0crwdne2889612:0 0
crwdns2934285:0crwdne2934285:0