Again, yes, I prefer actual studies to people's anecdotes like you do, but the purpose of these threads is to share these anecdotes, no matter if they are biased or not. For actual studies Google is your best friend.
After I became vegetarian (not vegan), I did notice a lack of strength. I then started taking creatine, which I didn't used to, and I got bigger and stronger than ever before despite not eating meat. So, creatine is important, especially if you don't eat meat. I tried stopping taking creatine, and I got very weak in two or three weeks and had some injuries because I was trying to lift the same weights as before.
5 g creatine is certainly a lot of creatine though. You only get about 1 g a day from eating a lot of meat. There are studies (Australian?) that shows that creatine raises dihydrotesterone, which is at least not good for your hair. When you get a blood test, you will also see high creatinine (creatine's afterproduct), which could alarm some doctors. In any case I don't think it is good to take 5 g a day indefinitely. I take 1 g a day even when I don't work out, which seems to help maintain muscle a little. When COVID is over, I will see if I can ever get back to where I was with only about 1.5 g a day.