Is there any advantage of getting a modem that's > $100 vs one that's like $50?

Probably not unless you have crazy fast connection

I have 100/10 not really crazy but I have like 10 devices on my connection lol.. Sometimes I drop (wired) and it's annoying af.. Prob not a modem problem but who knows

Pretty sure you just have way too much traffic for that connection

100/10 is enough for 10 connections. Enough so that you can even watch 10 Netflix instances at the same time.

Is this "modem" a combined wireless access point? I had to buy a more expensive one for the better signal.

If you're "dropping" connection while wired, it's probably the modem. You don't just drop connections unless something is going wrong.

not true

i stand by it

Only if your modem doesn't support 100/10.

Your router is another story.