"Product groups" are used in various processes, such as those in Service Parts Planning (SPP)
In EWM we use Product groups, Product group type for VAS, PP integration, Cross docking...
We have been maintaining Product group and product group type on T-code: /SAPAPO/MAT1 - Tab 'Properties 2" before SAP S/4 HANA 2023 release.
After SAP S/4 HANA 2023 release, it's no more editable on T-code: /SAPAPO/MAT1!!!!😂
After SAP S/4 HANA 2023 release Product group and Product group type is editable in T-code : MM02 (Material master)
----Detailed information -----
Open T-code: /SAPAPO/MAT1
Select Global data.

Check the Properties 2 tab
After SAP S/4 HANA 2023 release Product group and Product group type is not editale.

<Solution to edit Product group and product group type after SAP S/4 HANA 2023 release >
Open T-code : MM02 - View Basic Data 2

On the bottom you will be able to edit Product group and Product group type.

I hope this helps someone🤗
Additional information :
3343332 - Release information and restrictions for extended Service Parts Planning in S/4HANA 2023
Enhancement of "Flexible Segmentation", which allows you to create product groups based on BADI input (check note 3302797 for further explications)."
3302797 - Product group assignment with BRF plus – Qualifier BAdI