Steps to reproduce:

1. login to WebUI / Frontend
2. navigate to Configuration -> Discovery -> Create discovery rule
3. In field "IP range" enter ip-ranges seperated by comma until you reach 2048 characters
4. e.g. clone the default "Local Network" rule and add 192.168.0.1-254, as much as you can.

Result:
rule can not be extended if number of ipranges exceeds 2048 characters
Expected:
to be able to extend the ip ranges as usual while entering more than 2K characters.
like at least 4k characters or better 64K like it is stated in the manual here:
https://www.zabbix.com/documentation/5.0/manual/discovery/network_discovery/rule