I would not be willing to let the bike out of sight.
You should take a knowledeable friend along with you that can sniff out a dodgy bike. Much like generations of people have done before when buying a used car.
For bike sales, here is what I have done twice and will do so in the future.
I have been using my LBS since about 2018 (previous one closed). Because I actually use them, they know me and have worked on my bike and my grandson's bike. They are fully aware of how well they are maintained. During the pandemic, I mentioned that I was thinking of selling my bike. The owner asked how I would be selling it. When I said eBay he said "why not use my shop as the collection point, and then the buyer can question me about the bike while you step outside." To say I was surprised (and grateful) is an understatement. The owner went on to say that he was only offering this because he had confidence in the bike and could speak without having to lie.
Subsequently it worked very well. I sold two bikes via this method and both buyers told me how well it worked for them, they felt that they were getting a genuine bike. For me it was neutral territory and that a possibly dodgy buyer would never find out where I live to come back and steal the bike. I also believe that being able to offer this opportunity in the sales pitch increased the price I got and/or the speed of sale. On each occasion, I gave the LBS a small percentage of the sale price for their trouble. They did not ask for it and actually refused it, but I insisted.
This is something that only an LBS can offer, definitely not anything an internet seller can do.
PS: When I was preparing to sell my current bike, the LBS offered the same deal a third time. However, I have just given the bike to my grandson for a very nominal fee, so I wasn't able to accept their offer.