You are trying to step on a dime and get two nickels. This almost always means you step in dogshit instead. If you want great flannel sheets, you have two options:

1. Buy some ding dong Eddie Bauer flannel sheets and go with a known good. Now everyone here is a grumpy boomer who will state that quality goes down, but they don't know, they just like to repeat that phrase.
2. Ask for BIFL flannel sheets and post your pricepoint and don't shop your conclusions. Amazon and Kohls are retailers who sell 3,225 types of flannel sheets so mentioning their names obfuscates the issue as you need a specific brand and/or the metrics of purchase.

Metrics of purchase

Long staple cotton. Egyptian cotton. Supima cotton. Pima cotton. If you don't see any of these words on the package, keep walking. For the common man, those four terms mean the same thing.

GSM (Grams Per Square Meter) or in ounces per square yard is how flannel is sold. The best flannel sheet weights start at 160 GSM or 5 Ounces. Think the heavier the better/longer lasting, but weigh this against the warmth desired.