At around early May I decided to get back into solo queue. I placed in silver II and in two days I made it to plat IV (and no, I'm not making that up, my MMR was outrageously high). Then, a month later, I made it to diamond IV for the first time ever. Most people would be envious of that, but personally I wish I had never gotten back into it. Here's why: first off, I spent SO much time grinding non-stop. Looking back I could of done so many other productive things with that time, but I wasted it all on solo queue. Second, constantly grinding in solo queue made me feel super stressed and extremely anxious. I would constantly have to cross my fingers and hope to god I would get capable teammates. Sometimes I lucked out on the draw, and at other times I would get somebody who would troll, run it down, afk, or just whatever. And this happens a LOT in solo queue. It's a huge problem that has no easy solution, so by subjecting yourself to the grind you're basically signing up for that nonsense. And third and foremost-- I wasn't having any fun. You'd think I would feel somewhat accomplished after making all that progress in such a short amount of time, but no. Instead I felt like ripping my hair out and tossing my PC out the window.
Long story short, don't grind in solo queue. It's not worth your sanity, nor is it worth your precious time. If you're going to play this game do it for the sake of having fun rather than to achieve a high rank just so that you can boast about it. Because one, that's very unattractive, and two, no one's really going to care. People will call you trash if you're in silver, and they'll still call you trash even once you're in diamond. Just don't do it. Take it from someone who's been there and done that.