In rock climbing I am far from professional, I probably fall somewhere in between amateur and a mediocre climber, meaning I can usually boulder anywhere from a V5 to V7 and maybe occasionally a V8 if the route is set to my climbing style. On rope I go anywhere from 5.11-5.12a depending on the route again. After a while of climbing, for me 7 months in, you find yourself struggling to get past a certain grade of route and from what i've seen it's usually a v4 or v5 in bouldering and a 5.10d to 5.11a on rope. I found myself in this same place a few months ago and it's a very frustrating feeling that you're very strong in your climb but you cannot progress into a new grade, they just seem a little too hard and a little to technical sometimes. My first experience with the plateau was when I first started climbing and I had bought these climbing shoes from REI I think they were La Sportivas or something and I had bought them in my actual shoe size which felt pretty good but ask any climber and they'll all tell you, when climbing you must give up on having comfy feet. I was bouldering V3s and beginning V4s but my feet kept slipping off the wall or I couldn't get my toes to grab a tiny foot hold, luckily my gym in Dallas has a pretty cool program called Climb Fit with an excellent coach named Mario Stanley. Mario was the first one to inform me on the fact that at a certain point you will start out climbing what your shoes can do, so at that point my plateau was being caused by my inexperience with climbing equipment and was easily corrected with a pair of some toe numbing climbing shoes of my own (Over Exaggerating they're not that bad).
Skip forward a few months and i'm successfully doing V5s and a few rare V6s on boulder and 5.10d pretty solid on top rope but not progressing past these. I even got to the point where I wouldn't even try routes that were harder because I told myself I was wasting energy on routes that I wasn't ready for yet. After a few weeks of this i'm sitting at the gym frustrated as hell that I can't send routes and I run into this guy named Alec who tells me some of the best climbing advice i've ever heard. He tells me to stop focusing on the grade and focus on the moves, do a climb because it excites you or because a certain move interests you, make climbing about piecing together fun problems instead of grinding through a process that just gets you frustrated in the end. This helped me progress past my plateau because I wasn't focusing on a grade of a climb I was just focusing on how a certain climb looked, and because of that my footwork got better, I tried harder on routes, and I was sending routes that I hadn't even looked at previously. Obviously this was all mixed in with training and working out, and I also do yoga a a few times a week now.
The Plateau is different for everyone, whether it be equipment, training, or a mentality affecting your progression, I find in climbing it always helps befriending someone who is better than you and gaining wisdom from them. Plus the more climbing friends you have the less climbing seems like working out and more like a social experience you do with friends.