[Zabbix 5 ] How to resolve a mistake in template configuration without loosing data?

[MadMax-007]

I wrote a nice working template for specific units and it works great.
It tries to read out values from measuring points via SNMP and depending on the amount of enabled points Zabbix creates a corrosponding item and stores the measurement values.

But I made 1 small error: every item will be given the name of the measuring point.
This means (as far as I can judge) that once we change the name of a measuring point on the unit Zabbix Template will detect it and will create a new item for it and closes the old one.
This also means that we will have half the data and that old data of the item with the old name will be erased by housekeeping.

So... I know i can solve this by not using the name of the measuring point, but just the number of the input.
In stead of the name being formed by "T on {#SENSORNAME} " it should be "T on {#SNMPINDEX}"

But what will happen if I change this in the template? Will we loose all data and start from 0 again?

Is there a possibility to alter the Item ID's of the history to match the new Item ID's ? Or are there too many cross indexes?