Nah, delve gear is garbage level F tier. Once your 619+ its basically worthless if you got heroic 616 tier from vault. Go M+/raiding only once your ready to gear better in non-tier slots.
I also got the immortal spelunker title, beat the meta achievement and zekvir ??.
Delves will always be capped at a certain point. Its not a replacement for M+/raiding, your not getting mythic crests for solo’ing content.