Very good and understandable reasons.
I'm frugal with my car as well. Heck if it wasnt for rising prices I won't be considering getting an EV now and I'd still be keeping my 9yr old car for a few more years at least. Battery degradation is one of my main concerns. Even with new EV models with low 300's miles I'm a bit skeptical. I was thinking after 6-9 years I'd be having 25% battery degradation. Then factor in the fact that people getting closer to 80% of the EPA estimate. Plus take into account at least 10% buffer. 300mi would become ~165mi which is not going to be enough for roundtrips to most places I'd want to go to. Potential traffic, hot weather, hills... I don't want to stress out or charge every 3hrs of trip. Whereas 400mi degraded to ~220mi I'd still be comfortable with round trips from Sacramento area to Bay Area and one way to Tahoe. I suppose your GT upgrade is equivalent reasoning as my upgrade from Model 3/Y to Air Pure.
I just checked San Diego and LA area. Knowing SoCal traffic I'd say it's a very wise decision for you to go for 500mi. You can even go straight to Las Vegas nonstop haha. Fast DC charging 300kw for GT is nice too. I hope it won't be your last car
I'm checking if I could see myself upgrading to GT for the extra 100mi, but quickly looking at the price difference of ~$53k vs my Pure config that's an immediate nope haha. I checked distances and cities around where I live. Looks like Pure/T range will be fine for me. Should have more chargers in 5+ years time too. Just thinking now if I'm willing to shell out more for Touring to get glass canopy although as pretty as it is I will be the driver. Could be dangerous for my ADHD seeing all those extra details and sceneries lol!