Mobs? Like, BBI goblins, BBI skeletons, BBI bandits? Surely not BBI saurians and leapworms?
Mobs shouldn't be a problem unless you are heavily underequipped or using the wrong skills.

Get yourself an elemental sword or mace (fire sword is easy to obtain and enhance) and a regular sword: if you have fought THE Dragon you should have one of the dragon weapons if not get Carnation by purifying Lv.1 weapon item/s.
Elemental sword is for enemies too tough for your regular sword. Use it with magick skills like Ruinous Sigil or Great Cannon. You can add fitting enchantment when necessary.

If you can't get good melee weapons at least get a decent staff: if Gransys shops are not selling Lv.1 weapons yet, and you don't own a dragon staff, get Algid Bloom from one of two chests at Vault of Defiled Truth (and ofc enhance it, necessary tomes may be found in chest here and there). You can use staff skills against enemies vulnerable to magick but too hard for you to fight face to face or on enemies too resistant to elemental sword attacks.

Dragon forge equipment if possible - dragon forging is the core progress mechanics at the isle, without it you cannot rerefy your gear and pull off decent stats.

Shield should be the best you can get - you probably want to be able to Reflect (AKA Perfect Block) enemies attacks. Gold Rarefied Knight's Honor is sufficient vs.most enemies and is easy to rerefy in the first place. If you want to go max cheesy you can check Rusted Magick Shield (sold by Reynard) and Abyssal Anguish combo (when you'll finally be able to rarefy that shield). Blocking ability will be far from perfect, but torporing your enemies with full power sword is a sight to behold.

Armor? Get best you can get. But at the very start you may want to pick armor that you can easily rarefy, like Chimeric set
https://dragonsdogma.fandom.com/wiki/Chimeric_Armor_Set
and only later something local, like Immortal's Set.
https://dragonsdogma.fandom.com/wiki/Immortal's_Armor_Set

Yes, my problem is not really the normal mobs like goblins, my bad.
Currently I use the Crescending Roar, I'm going to try to rarefy it and see if I can kill the enemies that give me trouble.
Thank you very much for your response!