This is probably going to sound like an offensive post, but that isn't the intention, this is just real talk.
The problem is that the low elo players think that the skill gap between the ranks is small but the high elo players know the skill gap is actually huge. You are at over 300 games and in Gold 5, a high elo player can hit plat 5 in 1/4th of those games on a smurf. The games that you are struggling with feel like bot gamess at best to a higher elo player. I have 2 smurfs, 1 is in Gold 3 with P4 MMR and the other is in P2 with D5 MMR and I can tell you that when I go on my Gold 3 account, even with P4 MMR, the quality of players, both teams, is absolute trash and I wouldn't want them to play on a ranked team with me. Even on my P2 smurf I only occasionally see a player that is decent, but 80-90% of the people I get matched with on my P2 account are not people I would want to play with regularly in ranked.
If you want to play with high elo and see how you do in NORMALS then I can see you potentially finding a group, sometimes I queue with my silver/gold friends so they can see what higher elo is like. If you are looking to find ranked team then your chances are slim to none.
tl;dr: A high elo player knows how easy it is to stomp your elo because more than likely they have a smurf. Because of this no high elo team is going to want a low elo player. Look for a normals group instead.