First - I hate the iTunes / PC / iPhone interface. It always seems clunky and counterintuitive. Anyway - this is what I do. I don't know if it's the best way but it works for my needs.

I connect the iPhone to my PC by USB cable and start iTunes. NB Don't use too much internet while doing this because often the PC will use the iPhones data when connected this way rather than the home WiFi.

In File Explorer the iPhone shows up. I think you need to open the iPhone lock screen for this to appear. Open that and you can see the photo folders. There is one folder per month. Most photos are HEIC and also come with a video by the same name. I just cut all the "files" from all the folders and move them to my PC. This means my phone is now empty of photos. (I just keep a few photos I want to keep such as my Passport ID page etc.) NB. Photos I've received from friends on What's app are JPGs. If I've edited a photo (eg. cropped it) the phone saves a copy with a similar name. I think it just sticks an E in front of the number. I don't know what happens if you select a different key image. I'll have to try that.

I delete the videos but am careful to keep the actual videos I want to keep (not the ones duplicated for every photo) so I'm left with HEIC, JPGs from Whatsapp and actual videos.

I use an app on the PC called iMazing Converter. It does a pretty decent job converting images from HEIC to JPG. So now I'm just left with JPGs and videos. The way it should be. I manually delete the images that are the "before" editing versions and delete any photos I don't really want to keep.

It's time consuming and fiddly but I do this at the end of each trip.

I've tried a wifi photo transfer app and different methods but they all have worse problems than this above method ... for me anyway.

Good luck.