I don't think it's a cap. The connections are on the bottom of what you are calling a cap, that's a socket.
You don't need it anyway for modern cards if you are connecting all the pin power connections to the cards. I have been running Crossfire on the RVE10 since I got it with no power interruptions, just connect what the card asks for. It's more of a legacy provision for older setups.
Looks like I need to mod my case psu cover is only about 3/16 in from bottom I could not see connection . Think I can get buy running 2 rtx2080ti sli with out connecting EZ plug? Or cut a hole in psu cover.
You have two 8-pin connectors on each card and that will be enough. I am confident you will have no issues. The two 8-pin connectors will give you 300W and you'll get up to 75W additional from the slot. The card will use less than 300W at peak stress levels. If you overclock it, it will draw more.
Qualifying this also though by saying I am assuming your power supply to your system is large enough from your PSU. That goes without saying I think.
I'm not sure which MB you have, but personally I stopped using the bridge hardware and just use the onboard CF/SLI switch and it works perfectly for me on the RVE10. The bridges work too, I tried both. But the only reason to use the hi-speed bridge IMO would be if you are using an ROG labeled bridge for themed looks.