Druids in TT have some differences, besides the glaringly obvious "Druids can shapeshift, Clerics cannot" (Of course, the jankness that is BG3's implementation of Wildshapes kind of detracts from that)
Druids in TT cannot use metal equipment. Their armour and weapons have to be made of wood/leather to retain their connection to nature.
Druids in prior editions were required to maintain a neutral alignment (Neutral Good/Neutral Evil/Chaotic Neutral/Lawful Neutral), while Clerics alignment was dictated by their deity (And also influenced their Channel Energy ability and their auto-memorized spells, either healing living targets/harming undead with all "Cure Wounds" memorized for "Good" deities and dealing damage to living targets/healing undead with all "Inflict Wounds" memorized for "Evil" deities)
In prior editions, Druids have also been able to have animal companions too, with them being the defacto animal companion class with their companion scaling 1:1 with their own level.
Clerics and Druids tended to get different spell lists. With Clerics getting more "Divine" spells (Like Inflict Wounds, Harm, Holy Weapon, Dispel Evil and Good etc) while Druid gets more element/nature themed spells (Including some spells that are also in the Arcane Spell lists) like various Evocation spells dealing Fire/Lightning/Cold damage as well as Transmutation spells to change the physiology of themselves/allies.
While a Nature Domain Cleric can obtain a few spells from the Druid list, they maintained a distinct flavour to that of a Druid. Notably, being more of a "Nature Paladin" due to their ability to use metal equipment so plate armour, their deities favoured weapon and a metal shield and their innate list of Radiant/Necrotic based spells made them feel Paladin-esk (Especially in Undead prominent campaigns where their plethora of anti-Undead tools that Druids lack can shine)
Meanwhile, the flip side would be the Blight Druids which could access Death, Destruction and Darkness domains for some Cleric spells. But they end up being more of a "Plaguemancer" than a Cleric with their focus on vermin and disease as opposed to divine powers.
