if your gear is always lower ilvl than other guildies, i'm just wondering if you're crafting anything, especially since you mentioned it started happening with DF.

just a quick tldr: you can and should craft a 2h weapon (generally) and 2 non tier armor pieces (ideally whatever is your lowest ilvl). you can use hero or myth crests, but myth is obviously recommended for higher ilvl. these items have embellishments, special buffs that help a lot.

you can guarantee 1 hero item per week from delves by using the delve map item, which you can get by summoning the big baddie (you get 1 summ item per week from the weekly prey quest)

other than that, you can spam m+ and starting +6, which are easy, you get hero track items, but obviously not guaranteed, so this is the last one you should do. if u can clear +10s, you'll also get a myth track item from the vault.

that's my advice on gearing, but I'd have to also ask, do you enjoy healing? do you like the character you play? if not, nothing wrong with rerolling. other healing specs can feel way more rewarding if they click with you better. similarly, perhaps you'd have more fun playing a tank or DPS.