I feel like the lack of low level RDF (10-79) makes picking up roles like tanking come endgame much harder

The easiest way I have found to learn to tank is to specifically play tank from the low level and do the dungeon finder thing. Pretty certain for most of my tank toons in retail in the past I have leveled via the RDF. I have been playing a pally and now im starting to approach 80 and now (due also to a number of toxic attitudes) I feel nervous to pick up that role, I dont feel like I have had that massive amount of practice and build up to endgame that I had previously. Not saying its impossible by any stretch but I certainly preferred the playstyle of dungeon spamming and learning that way (and yes, ive been in the group finder for the last 45mins and we cant find a healer).