If you want to achieve the look shown in Figure 2, please use this checkpoint; otherwise, the portraits may turn out in a realistic style (though that looks pretty good, too).
https://civarchive.com/models/2357432/tulpainterly-xl?modelVersionId=2651420

Illustrious-style oil painting LoRAs are relatively scarce, yet I happen to be quite fond of this aesthetic. Consequently, I decided to try training one myself. However, the results seem a bit inconsistent—sometimes the output doesn't quite capture the look of a true oil painting. If there is enough interest, I will work on expanding the training dataset to improve it. Using the model is very simple: just include the trigger words. Below, I've included one of my favorite generated images.
It turns out that what I actually needed to train was a checkpoint, not a LoRA. However, I'm not quite ready to train a checkpoint myself just yet—but fortunately, there are some excellent ones already trained by experts available on Civitai! I've actually used them before.
V1↓

V1.5+tulpainterly-xl


Haha, it seems it unintentionally achieved an unexpected effect. Before using Lora...



After using LoRA