It sounds like you’ve been able to crack the case of the GPU-related crashes with the clock changes you’ve made which is super! 
The other errors you’ve been experiencing (2014, etc.) will be due to a separate cause.
You can use something like Wireshark to monitor dropped packets during play, but it is a bit of a learning curve admittedly.
I notice you’ve included your experience in INVESTIGATION: Disconnects (Error Code: 2001, 2014, 3013, 4001) & General Connectivity Issues which is particularly helpful as the team are monitoring this and aware of a recent increase in errors.
I’d still recommend continuing to investigate the dropped packets in case of a localised cause, and if you change your mind on wanting a refund I can easily help with that.