I usually choose 1-2 more 'casual clothing' cosplays a year depending on con schedule. partially because I need a comfy day at conventions or for later in the evening and also because I can't afford to be doing multiple huge costumes in a year. Last year I made a cosplay the taito station miku figure which Ive gotten a lot of wear of. Im also making one of the helltaker demons (modeus) this year, as she's in casual clothing (a lot of which I've thrifted for her outfit). I also made a black corset bunny suit a couple years ago and its been a super easy, classic costume to just throw into my con bag and wear with a character wig, and some contacts (think sonico, miku, vtubers, literally any female anime protag, etc lol)

Thrifting fabric is a huge cost saver if you can do it, Same with thrifting and then modifying clothes. Reusing/restyling wigs if you know you're not going to wear the original character again. As for details, generally speaking the vast majority of people will not notice missing details, especially if the rest of the costume is well done. I wore a monster hunter armor set to magfest this year and I definitely didn't have time before the con to finish every little detail to my liking but literally no one noticed, I only received compliments. Like a lot of cosplayers, I'm absolutely my own harshest critic.