Ghost1801

The Red Devil or the Sapphire Nitro+ are one of the best 5700XT cards so far in terms of temps in my opinion. Don't get the ASUS TUF one as its been reviewed by several youtubers and found out it has bad cooling.

The 2080 Super is going to outclass the 5700XT in many games.
 
The 5700XT was made to compete with the 2070ti/super. But with that said, it's still a good GPU for 1440p gaming at high-ultra settings.

Your going to need a CPU upgrade your going to run into some bottlenecks.
As far as GPU's I would look into the 5700 or 5700xt

If you keep waiting, you'll never be able to buy your card. Just buy what you need for now. A good alternative would be to go with AMD. Consider the AMD Radeon 5700XT, its good for 1440p gaming and much cheaper.
 
Your processor is also a bit old. A 2080ti will work, but you might start to experience bottlenecks on higher end AAA games especially if you ramp up settings on the more CPU intensive titles like Assassin's Creed.