This is what finetuning has been all about since stable diffusion 1.5 and especially SDXL. And even something StabilityAI base models excelled at in the open weights category. (Midjourney has always been the champion, but proprietary)

Sadly with SAI going effectively bankrupt things changed, their rushed 3.0 model was broken beyond repair and the later 3.5 just unfinished or something (the api version is remarkably better), gens full of errors and artifacts even though the good ones looked great. It turned out hard to finetune as well.

In the mean time flux got released, but that model can be fried (as in one concept trained in) but not finetuned (this krea flux is not based on the open weights flux). Add to that that as models got bigger training/finetuning now costs an arm and a leg, so here we are, a year after flux got released a good finetune is celebrated as the next new thing :)

Wan 2.2 is a video model people have been using to do text to image recently that I think solves this problem way better than Krea in the base model. -- https://www.reddit.com/r/comfyui/comments/1mf521w/wan_22_tex...

As others have said, you can fine-tune any model with a pretty small data set of images and captions and make your generations not look like 'AI' or all look the same.

Here's one I made a while back trained on Sony HVS HD video demos from the 80s/90s -- https://civitai.com/models/896279/1990s-analog-hd-or-4k-sony...