Questions about needles for my turntable

Hi! I’m new to this subreddit, but I hope it’s the right place to ask this question.

I have an okay Soundesign turntable I picked up a few years ago. Nothing special. I’m not sure what the model number is but if I can find it I’ll add it in later in the post.

I need to get a new needle for it, but I have a few questions. I know the one that’s on it right now is a Realistic brand “Diamond Needles” Stereo 110. My first question is whether there may be any equivalent needles I could get since I’ve been having some trouble finding the exact same one?

My next question is about another stylus. The turntable is three speed (33,45,78) and I’ve recently acquired a large stack of several hundred old shellac 78s. I’ve played 78s on this turntable with the 110 needle before but I’ve been told that’s probably not something I should do. I’ve read a bunch saying that if you’re going to play 78s you need to get a specific needle because ALL 78s have wider grooves than 33s and 45s and you risk damaging your needle as well as just not getting as good of a sound from the records. So if I wanted to play these 78s is there a stylus with a larger needle that I could just swap out with the 110 any time I want to play 78s? And is it really true that all 78s, whether they were pressed in the 1920s (the oldest I have) or into the late 1950s, are all going to be wider grooves than what’s typical for vinyl 33s and 45s?

I’m just looking to find the least expensive and best way to get the needles I need to listen to my shellac 78s as well as all my vinyl. Any information or recommendations would be wonderful! Thanks!

Edit: the back of the turntable says “SOUNDESIGN STYLE NO. KMTR 458” if that helps with anything. I can’t find any pictures of turntables that look the same online even when searching for that model but maybe someone with better research skills and resources could.