I won't claim to speak for other GMs, but I for one care far less about the character concept than what I see on the player's profile. What I mean is, I'll click on the player's name and see what info has been added to the bio. I'm looking to get a sense of who a player is. Just a little something about the person I may end up playing with. If there's nothing there, or nothing that gives me a small glimpse into who this person is, I typically move on. But I should stress, that's just me. Other GMs will obviously have their own criteria. I'll also take a few moments to check out any previous posts the player has made. I'm not looking for any particular info so much as any red flags. If I see previous posts where a potential player posts some kind of rant, or a response to someone else that's insulting or otherwise unpleasant, I take that as a sign of things to come and dismiss said player. Now, I doubt that these are things that affect you in this case, so the rest comes down to luck, perseverance, and timing. The simple fact of the matter is this: on Roll20 there are far, FAR more players than GMs. For 5e in particular. The trick is not to give up. I would also submit the following; it always strikes me as a bit odd that people look for and expect to join a long term campaign right off the cuff. I'm of the opinion that it's a bit nuts to expect a group of random people who meet on the internet to magically create a successful long term game. I would suggest that you try to join any one shots you can as well. And if possible, consider joining games other than D&D as well. The goal is to meet as many GMs and players as possible and see who you gel with. Over time, you'll find people who you have fun gaming with and you will naturally start to create an increasingly more regular group as you discover one another and find that you play well together. Just my two cents. Good luck and happy gaming.