Must admit I don't use Ebay much these day's as a buyer.
FB Marketplace is great for bargains and even rare stuff, but you have to be prepared to sometimes really bend over backwards to buy something from someone (working around their agenda, chasing up etc - ridiculous really!).
Back to Ebay, I've done ok recently selling a couple of items (a bike, and a guitar amp), but I think that's more to do with the fact that they were both fairly low cost, and cheaper than the same / similar items listed (a few dreamers), because I genuinely wanted to sell them and make the room. Lots of watchers who clearly had no intentions of purchasing. Just got to wait it out, if it's the right price, it'll usually sell within a month I find.
My favourite way to buy bike parts these days is a jumble. Everyone is always so friendly, you can inspect the item, chat about it, perhaps a little haggling. Wonderful. I just make a list of things I need before going and aim to stick to it (yeh right!). But I'm quite lucky in that there are at least 3 x bike jumbles fairly locally, often twice a year.