I feel like bosses or entities should not be *strictly* immune to a specific damage type (ex: Mati being immune to physical damage and swamp golem being immune to magic damage), they should be resistant to the said damage type. Having a strict immunity (especially with no way to bypass, such as a spell that converts phys to magic damage or similar) to a specific damage type forces players to spread their skill points across different damage types, which not only discourages building up a class (such ad investing in guns, bows, swords, or magic weapons), but makes it harder for players to handle late game entities due to a lower damage output from spread stats. Many games such as the Dark Souls series, Dead Cells, Helldivers (to an extent), Risk of Rain 2 (for better synergies or builds), and other games encourage (and actually make it a necessity) investing skill points to eventually end up in a “class” or “specialty” (Dead Cells uses exponential weapon damage scaling, dark souls has weapon requirements and scaling, risk of rain has synergies) allows for more ways to play through the game and doesnt force the players to feel as underpowered in late game/post game quests.
Pomegranatapfel