The champ will be which ever one you can afford and you can actually get your hands on.
As to 'better' that's entirely a matter of personal opinion based on wants and needs. As you say, your games aren't that demanding (today) and the 750ti was ok for your wants graphically and the needs of the games detail settings and resolution. On your old monitor.
Move to a bigger, better, stronger, faster, higher resolution and the 750ti isn't upto snuff. Thats going to require a bigger card just to get you back to where you were on the new monitor. If that's all you need, then a mid grade card is good enough 1660ti - 2070Super or Rx 570-5700.
So the question really isn't 'which is better' because there's always a 'better' card for a few $$$ more, the real question is 'what's better for you'.
Do you plan on keeping this card for several years, do you plan on never playing anything but those games, what are the chances you'll want to play something more demanding, what are the chances of War Thunder 2 or Royal Revolt Apocolypse being the next thing for you, and it ups the graphics settings considerably.
Not really much point in buying a gpu that's only barely good enough for now unless now is the same thing 3 years or so into the future.
I'm playing the same games now that I was 5 years ago, on my prior gtx970, but with dlcs, mods, updates, new challenges, the graphics are more intense and the deviation between what I had and what I've got now isn't as big as it was a year ago.