Just a list of suggestions for incentive to play a pure ranger-
Give rangers their FEs at 1, 4 and 8
Give rangers a pure perk at lvl 8 to be the cusp of their concept.
Ranger Knight - Heavy Armor Proficiency, Skill Focus - Lore
Hunter - Weapon Specialization Longbow, Bundle of Arrows on rest
Gloom Stalker - 1d6 Sneak Attack, Stealthy
Beast Master - Item called 'Leash', with 1/day Greater Magic Fang and 3/day Magic Fang, OUB PC