I’m glad to see you’re sticking to the Apple Ecosystem. 😜
Regarding upgrading, I’d rule out the iPhone SE. The A13 Bionic is powerful, but it’ll show its age quicker than you’d think. The same goes for the iPhone 11 if that ever crossed your mind.
The iPhone 12 is a better choice, in my opinion, and more bang for the buck - albeit $200 more than the SE.
Ultimately, it comes down to money. You can run maximum graphics on the SE, but there will be some heat and minor to moderate lag. The 12 will perform better, and you’ll have minimal, even no lag, with little heat. It honestly depends on what you want to sacrifice - money or performance.
Let me know if you need any more help!