Scripting more efficient monsters for game

I currently own some joke game that i made originally in august which was originally just something funny for me and my friends but its ended up with nearly 400k visits combined from the old version and the one i had to remake for certain reasons

its area 51 themed and for the monsters around the map, i made regular monsters and welded them to an image of a character since my knowledge on scripting is very minimal.

but there has been a lot of bugs with this as the characters get stuck in the floor, and i cant add weapons since zombies respawn without the image attatched resulting in invisible monsters killing people and it ruins the fun

they also cant jump which is annoying

the game is Survive Genshin impact in area 51 and i know it has some um models but the zombies are my own creation and i really want them to be able to work properly so its more enjoyable

to summarise it im just wondering if someone can help me out with making them

  • able to jump
  • respawn (not a main priority) but along with keeping the images
  • solution to them glitching in the floor

I DO NOT want to get rid of the random images chasing you, yes it looks really poorly made but i want the game to still feel like some random joke i made for my friends

image shows how they dont jump, video shows them glitching into the floor

zombie