re: coinmarketcap prices and when you sell your bitcoin for $3500, there’s someone else on other end buying it for 3500

One thing that has long puzzled me was the inter-relation of the trading pairs available on the various exchanges and how they would impact the rolled up prices on coinmarketcap.

As a result I learned not to trust or make decisions based on coinmarketcap other than to use the information there to help me predict what OTHERS would do. Since I mostly trade BTC pairs, CMC would give wrong information for that.

My intitial issue and question was this: let’s say I buy 100 BTC worth of LTC at a certain price, when BTC happens to be priced at $10k, with the goal of getting more bitcoin later, when the price of LTC in BTC terms goes up.

So I wait and wait. There’s a crash and cycle this and cycle that, and bitcoin crashes down to $3500 but I see that my LTC bag has gone up in BTC value. Let’s say 5% for this examples so I sell my LTC for 105 BTC

What I’m confused about - does my trade of BTC to LTC, in or out, impact the USD price? I know there’s a separate LTC market but surely the BTC supply and arbitrage angle has some impact. I don’t know how much or if it’s direct or indirect.

If I sell the LTC for 105 BTC for whatever price and BTC happens to be $3500 at the time, does that boost BTC’s USD market at all, specifically and directly?