Long story short, without a fully functioning paint shop in Texas, accelerating Model Y probably makes little sense.
One reason it makes little sense is there is a much better alternative, export of Model 3 for Asia Pacific and Europe from China.
Thank you for your very informative reply. When Texas was announced as the location for the next U.S. Gigafactory, Musk was quoted as saying "The location will be where Tesla will build Model 3 and Model Y vehicles bound for the East Coast. The 2000-acre facility will also be home of the Tesla Semi and the upcoming Cybertruck."
I haven't seen further details as to which of the products would be manufactured first at Texas GF. I think the Q2 Update report said combined M3 and MY production capacity in Fremont was being raised from 400 to 500,000 vehicles. Since Tesla believes MY should ramp over time to sell higher volume than M3, it suggests that while accelerating MY at Texas is off the table, it may be the first vehicle Texas GF will produce. If this is true then a fully functional paint shop would be in the first group of completed buildings at Texas GF. Hopefully it will be the same "state of the art" paint shop Tesla says is being built for the Berlin GF!
Have you seen any information that suggests Cybertruck will be mass produced at Texas GF before MY? My guess is substantial production of MY/M3 ahead of CT. Texas would be the fourth location for MY production (Fremont, Shanghai, Berlin then Texas), and setting up lines there should be routine by the fourth time. I believe Cybertruck is slated for Q3 or Q4 limited production. But the pace of build at Texas would suggest they want parts of it to be operational sooner.