Advice for when one AI gets way ahead

[Your Friendly Milk Husband]

I've been trying my hardest to win on the Deity difficulty lately, but I've noticed a pattern in most of the games I've played: I'll generally be playing on-par or below the AI on my continent, discover cartography to reach the other continent, and discover an AI who has pulled incredibly far ahead!

For instance, in my most recent game as Pachacuti, the majority of the players (including myself) were ranging about 100-150 science by the Renaissance Era. However, one civ (I believe it was Saladin) was making over 300 science per turn! It feels as though there is always "that one civ" every game that is dominating the game before you even meet them.

What are some recommendations for stopping, or at least competing with, these kind of AI players? My go-to plan would generally be an constant barrage of nukes, but oftentimes the game will end by the modern era due to their equally absurd tourism (AI can spam rock bands like nobody's business) or even through diplomacy.

[Exemplar]

i often refer to those as "runaway(s)". depending on map size there can be more than one and generally it's the result of a failure to launch civ, for whatever reason, being consumed by a fortunate neighbor. this happens more often on fractal map, or when you increase ai opponents for map size in advanced options.

players can and should be doing exactly the same thing, (taking early advantage and consuming neighbor(s)) but then if you're trying to play a peaceful game it's more noticeable, i guess. what can you do about it? anticipate it by having a projectable military force? if you're going to let it sit there and grow, you're probably out of options.