I am a level 5 endorsements player at the precipice of gold (1922 Tank, 1956 Support, 1974 Damage, and 1991 Open), so I know a little bit about getting along with people. I absolutely never group up for Competitive. I’ve tried it with friends, I’ve tried it with LFG, etc, and it does not work.
Kaawumba details why the LFG option is a penalty in the “Matchmaking and Groups” subsection of his excellent guide: How Competitive Matchmaking and Ranking Works (Season 28+) - #2 by Cuthbert-11649
I am futilely asking for Role Queue to be Solo Queue only in my topic: Competitive Suggestion - Solo Queue
I think Competitive is harmed by groups, always. Group games are the most imbalanced for me. There are 9 game modes available to play in groups that are not competitive. Maybe there should be one that seeks to determine how good your group of friends are, (Team Queue), but otherwise, let’s find out how good YOU are in Competitive by requiring you to Solo Queue.