Just to push back again against the idea that healers have more responsibility: if DPS interrupt the correct spells and use cooldowns correctly, healers have basically no responsibility in anything other than very high keys. Like DPS buttons by and large are far more important. It's kind of a meme in the other direction bc ppl don't understand how the game works.
And for tanking, I pressed w thru most dungeons in S3 and got to 3200 speccing and gearing 100% for damage and being frankly a mediocre tank. Lol think people talk themselves out of doing stuff but imagining it is harder than it is. I used to do the same with routes but it honestly does not matter that much and eventually you'll get over the anxiety and start getting annoyed when you out DPS meta players.
I really think the best thing people could do if they want to actually improve in all layers of the game is to try and really learn to DPS at a high level. It will force you to learn tons of subtle things about the game, including how unbelievably frustrating it is when timid tanks pull like two mobs when your cooldowns are up and could destroy a pack in 5 seconds.