If Qualcomm decides to stop support for the SD 750G, then you may want to support with all your 
, it isn’t possible anymore to support all the chips which run their own specific proprietary firmware. Unless you resort to very advanced stuff like using InternalBlue to patch the Bluetooth stack. This is an exception to the rule though, and requires very specific expertise though, which is realistically not available at Fairphone the company.
Edit: given your post at Why did Fairphone use an outdated SoC for the FP4 even though they knew Qualcomm would not support it longer? - #9 by amoun I can safely state you are unaware of these issues.