Counter argument, devil’s advocate:
You get what you pay for. Yes, ebay fees seem high but you get access to a bigger market of buyers, you can sell in other ways, word of mouth, Swappa, Craigslist. I’d say you don’t really have a leg to stand on saying its just expensive, I’d say use it and accept the costs or don’t use it, find an alternative.
These are businesses for profit, they offer a service for a fee. Someone has to pay for the software developers, datacenters, hardware, electricity, etc.
Personally I tend to buy very little full stop and I tend to buy the best item after careful reviews, so I tend to not sell anything as I don’t have either excess products or bad products to offload. I also tend to not buy from ebay as, for example with Amazon, Aliexpress, Gearbest, B&H, Newegg, etc, there are plenty of options. I checked my orders, I bought two items on ebay each about $10 to replace items I’d lost, this last year. The expensive items I typically buy direct from the manufacturer to get the least grey support. Example is my most expensive item was the OnePlus6 over a year ago, bought direct from OnePlus.
The need for Paypal has vanished for me, I get protection with my creditcard and use that directly if I do buy from ebay.