GPT and Blender are both generic terms, unless the combination is already being used or is registered then it appears - and of course this is not legal advice - that there is no infringement.
Indeed I think registration of GPT before USPTO has been refused because it is generic.
You might be breaching contract, assuming you're using ChatGPT behind the scenes, no idea; in theory they could require you not to use GPT in your product name.
Of course, being in the right is not enough. Companies/organisations can still go after you.
> Blender has been registered as a trademark by Blender Foundation in USA and EU. It has been used by Blender Foundation since 2002, and it’s a well recognized brand now. Although the name ‘Blender’ is a generic word (for a mixer), in the context of products or company names related to software it’s protected by trademark law.
It seems like you're doing a great job, and these are some low hanging fruit you can address just to make sure you're not violating trademark law.