Okay, this is a little embarrassing, but basically I have 1.5 bitcoin on a ledger s that I put on there in early 2018. I have since moved abroad and had issues logging onto the regular marketplaces/coinbases, so I just stuck my ledger in my safe and didn't touch it for 2.5 years. I finally decided I should plug it in and check on it, and see now there is a Ledger Live option. I followed all the instructions, I updated the software of my Ledger, and I added accounts, but it will not show that I have any bitcoin! I'm honestly panicking a little bit, trying to stay calm, but I'm really freaking out inside.

Here is what I have done already:

I reset the Ledger using the 12 word option (do I need to do the 24 word option?)

I deleted the apps and then reinstalled them

I deleted accounts off of Ledger Live and reinstalled them

I cleared the cache on Ledger Live (the program crashed so I will try it again later)

I am 100% sure my bitcoin were on the Ledger device, so there is no question about that.

Am I missing some step to get my coin to connect/register on Ledger Live?

Please help, I'm a bit clueless about all of this (thus why I haven't touched them for 2.5 years) and so I need the most basic instructions to troubleshoot! I just want to make sure my bitcoin are secure on my device. Thank you!

I think that the problem may be the derivation path.
I've just did a test with Ledger live and (for me) it "offers" to show only SegWit compatible and Native SegWit address.

OP, can you please try to install another wallet?
Maybe you can install Electrum, but make sure you get it from electrum.org and check the signature ( https://electrum.readthedocs.io/en/latest/gpg-check.html )
Electrum works with Ledger. When asking select Legacy addresses.

The questions is, where did you get your Ledger device? The risk of getting a tampered Ledger device is pretty huge if however you decided to bought it from unauthorized reseller and not from their official website.

The fact that entering a 12 word recovery seed phrase means that you also generated a length of 12 word seed upon setting up your device initially. Have you used this article as a reference for recovery?
[1] https://support.ledger.com/hc/en-us/articles/360005434914-Restore-from-recovery-phrase

Since you didn't touch your Ledger device for 2.5 years, a number of firmware updates came out in the meantime. In your OP, you didn't mention if you installed the latest firmware update or not. You just mentioned that you installed the latest software, I assume this is Ledger Live. You need to enter the exact 24 words in the same exact order as when you originally set up your wallet. These words are only entered on the hardware device itself, never in the Ledger Live software app. If some app asks you to enter you seed, it's a fake/phishing app.