Hi mhh,
(tldr I know its hard but wait 1 more year)
I am sure you know that there is a lot of chatter about an upgrade coming soon as I believe you delayed upgrading last year already because of this.
My perspective, especially after JB's comments in the last earnings call that they have looked and are not planning one at this stage, is that an upgrade is more likely early next year, possibly announced as part of the Model Y announcement in H2 (maybe Q3). Given that the model 3 is using a new motor that seems to be less prone to overheat and is significantly more efficient than the S/X motor this seems inevitable. I think it will be early next year as they seem to still have good demand for the current version and they are more likely to time the update to the loss/reduction of the tax rebate in the US.
I guess you have seen the recent track day of the model 3 and I will be interested to see if he tries again with regen on (as well as upgraded breaks) and see if it still doesn't overheat.
Model 3 Track Day: Laguna Seca.
Here is some reasons why the new motor is better than the current S/X
Tesla Model 3 Motor — Everything I've Been Able To Learn About It (Welcome To The Machine) | CleanTechnica. It seems the roadster also did not overheat during the reveal unlike the reveals for the S/X where they had lots of issues.
Lastly it seems Porsche/Jaguar are targeting track performance as an advantage but I think Tesla will respond with S/X, P model 3 and obviously they already have with the Roadster 2. Hopefully Tesla can get (or has already) some good suspension/break engineers with track experience. Maybe the performance model 3 will provide some clues late this year.