@alanmz5I think I'm missing something here, after nexus devices Sony is the best OEM with less bloatware.
If it's a third party app, it's not up to Sony to guarantee compatibility, that's up to the developers, I understand that you want your phone to work certain way, which you have the option, download other home launchers or apps that are compatible and if you really like certain third party app, make sure to contact the developer to address the compatibility issue.
I dont understand your last post
"TBH, it may not be simple but quite honestly, if a third party app developer can do it, so can the manufacturers. Re the bloatware, you're quite right.
Al."
Third party developers are in charge of their apps not adapting android source code to work on the devices