First, welcome! ST refugee here too. You'll find a lot of us in this community.
If you haven't come across Rick's thread it's a good read.
The neighbors list is devices capable of repeating that are directly connected to the hub. They may or may not actually be repeating. The other devices are one hop away. If you have child devices they are non-repeating devices connected directly to the hub. If you have devices that are more than one away they won't show up. Also this is a pretty dynamic table - a snapshot of a point in time. It's good as a general indicator but it's not a complete routine table.
Basically you want LQI high and in/out costs low (but not zero). You have a fair number of repeating devices with high in/out costs. May be contributing to your issues.
For comparison here's what mine looks like.
I would also take a look at the potential for wifi interference. That can be a real issue, especially if your HE is sitting right next to an AP. There was one guy a few weeks ago who was having zigbee issues and it turned out his mesh network node made a great "stand" for his hub. Not so much 
Are those Ikea bulbs also trying to repeat? Sengled bulbs do not. If the Ikea bulbs do, I would get them out of there. Zigbee bulbs that act as repeaters really wreak havoc. I did some searching online and I wasn't able to find anything definitive but I would suggest removing the ikea bulbs and see if that improves things overall. Many of us run separate hubs dedicated just to bulbs - in my case I have a Hue hub that manages all of my smart bulbs. You can also use a dedicated HE to do it.
I've generally shied away from Ikea repeaters. I find they don't seem to work as well as others. But other folks may have a different experience. I use smart plugs - the ST ones work really well and I've had good luck with INNR and Sengled. Dunno what the deal is with my drawing room lamp east though. Will have to check it out.
