if I have a wallet with 100$ and I sent out about 90ish transactions from said wallet, could someone check the ledger and identify said transactions came from the same source?
Yes if you are not careful, I think it is much better to practice using different address for receiving coins and never use again previous addresses. I'm not really sure if they can be track even if you use different address, but I'm sure that's a good practice.
LOL if I was going to use it for something very bad I'd setup software to gen random wallets, move funds to said wallets then transmit the wallets so that it looks sp00ky, but im not using for anything bad lol <3