Increasing/decreasing while staying in pattern

Hi everyone, hope y’all had a great Thanksgiving. I’m running into a problem… I want to create my own patterns for something simple to start with, and those are headbands. Now, I don’t want to make a headband where you cast on, say, 20 sts and knit the whole piece without increasing or decreasing. There’s tons of stitch patterns I can use, and that’s all fine and good because since I’m not adding or subtracting stitches I can just knit away, easy peasy. But say I want to start with a few stitches then increase until the headband is like 4" at it’s widest, then decrease back down to a few stitches and join it. And say I want to use a particular stitch pattern that I like, but that stitch pattern requires a multiple of 4 sts + 3. It’s one thing if I’m casting on sts in those required multiples and not increasing or decreasing, but how do I use this stitch pattern from start to finish when the number of sts are going to vary? Now, with stitch patterns like garter and stockinette this is not an issue because they don’t get affected by increasing or decreasing. You stay in that pattern no matter what - you can add or subtract sts as you go. But if I use a stitch pattern where if I increase or decrease by even 1 stitch, that pattern gets thrown off. Is there a way prevent this and stay consistently in that st pattern? Is this where double increases/decreases come into play? I hope I’m explaining this ok, it’s hard to put into words. Your help will rid me of much head scratching.

Would you mind to post a link to the stitch pattern you plan to use? It would help us to give a suggestion on how you could do the increases/decreases.